Transboundary Implications of China's Weather Modification Programme

Abstract

In recent years, China has expanded its national weather modification programme to exploit climatic resources and adapt to climate change. The unprecedented scale of China's weather modification programmes has raised concerns over potential environmental impacts, including transboundary impacts. This article analyzes the domestic governance of weather modification in China and the extent to which this legal framework satisfies China's obligations under customary international law to minimize risks of significant transboundary harm. We find that existing arrangements do not satisfy procedural obligations under customary international law; nor do they adequately address the risks of environmental impacts associated with the increased use of weather modification. Procedures for transboundary environmental impact assessment (EIA) and engagement with regional neighbours are needed for China to comply with international law and promote stability in the region.

1. INTRODUCTION

China is implementing a large-scale programme of cloud seeding, which has attracted media attention worldwide.¹ In 2022, China experienced the most severe summer heatwaves since records began in 1961. Daytime temperatures were above 35°C, lasting for over two months.² The associated drought affected transportation, industry, food, and hydro-electricity production for close to one billion people across 17 provinces.³ In response to these crippling drought conditions, China imposed tight water-consumption restrictions and deployed aircraft and drones to seed clouds to enhance rainfall.⁴

Weather modification by cloud seeding involves injecting particles – such as dry ice, silver iodide or salts – into certain types of cloud to enhance precipitation or suppress hail.⁵ Depending on local geographical and meteorological conditions, cloud seeding operations can be air-based, with particles delivered via aircraft or drones, or ground-based using generators, canons or rocket launchers.⁶ Developed by American scientists after the Second World War, weather modification techniques focused initially on mitigating extreme weather events and increasing rainfall for agriculture.⁷ In recent years, cloud seeding has become a ‘long-term water resources management tool’⁸ around the world, to alleviate water shortages and enhance hydro-electricity production.⁹ Some states, including China, also use weather modification to mitigate hailstorms, although the scientific evidence for hail suppression remains inconclusive.¹⁰

Weather modification has been researched for over 50 years in China and other countries, yet its environmental impacts remain understudied and poorly understood.¹¹ While weather modification techniques have obvious benefits, they also pose risks of adverse impacts.¹² Altered precipitation patterns can affect plant and animal communities, land structure, and hydrology.¹³ In addition to the direct risks of weather modification, unsuccessful cloud seeding operations can increase the impacts of droughts, floods and other weather disasters, for example, by increasing hail or reducing precipitation.¹⁴

The risk profile of weather modification differs depending on the scale and type of seeding agent deployed. Some studies suggest that silver iodide could have accumulative properties, with risks of persistence in the food chain and impacts on biological diversity.¹⁵ The United States (US) Weather Modification Association considers the annual dispersal of three tonnes of silver iodide in Canada and the US to be environmentally safe.¹⁶ However, the World Meteorological Organization (WMO) Statement on Weather Modification recommends that ‘any plans to use either a massive quantity of such a product or a different seeding agent should be accompanied with a preliminary evaluation of its potential effects on both environment and human health’.¹⁷ The WMO is a United Nations (UN) agency, which facilitates information exchange on weather modification. The WMO Statement on Weather Modification articulates authoritative but non-binding guidelines for conducting weather modification projects.¹⁸

There are concerns, both within and beyond China, about the negative impacts of weather modification at the scale of China's expanding programme.¹⁹ Weather modification activities could affect the regional distribution of rainfall, potentially depriving downwind areas of their natural precipitation.²⁰ In some cases, weather modification could also increase rainfall: studies demonstrate that seeding agents such as silver iodide can seed clouds and thus enhance rainfall up to 200 kilometres (km) from the target area.²¹ Therefore, there is a clear risk of ‘extra-area effects’ on ecosystems and communities beyond the target area, including ‘the possibility of creating severe weather or floods’ or ‘increasing rainfall in one local region at the expense of rainfall in a neighbouring local region’.²² Within China, this issue arose in the 2000s when local governments in provinces such as Henan, Guanxi and Shaanxi accused each other of stealing precipitation (or ‘cloud theft’).²³

Of perhaps more importance are concerns that weather modification activities could have detrimental impacts across national borders.²⁴ Controversy over potential transboundary impacts of weather modification has persisted since the 1960s,²⁵ and these concerns continue to feed geopolitical tensions.²⁶ It is not the purpose of this article to assess whether any of China's weather modification activities have in fact caused, or are likely to cause, significant transboundary harm. A claimant state would face major challenges in litigating a claim based on actual harm because of the difficulties in establishing a causal link between a specific weather modification activity and any alleged transboundary harm.²⁷ It may be possible, however, to demonstrate that the increased risk makes harm ‘likely’. With the present state of science, it remains extremely difficult to demonstrate that weather modification activities cause transboundary impacts (for example, disruption of regional climate systems, changes in transboundary watercourses). Yet, in accordance with the precautionary approach recognized under international law,²⁸ these uncertainties should not be used as reasons for postponing measures to prevent serious impacts from occurring.

A prominent example of these concerns is the ongoing tension between India and China over China's ‘Sky River’ weather modification project on the Tibetan Plateau.²⁹ Since 2016, Tsinghua University, Qinghai University, and the meteorological bureau of Qinghai province have been working on the Sky River Project (Tianhe in Mandarin),³⁰ in collaboration with a military contractor, the Aerospace Science and Technology Corporation.³¹ The project is expected to transfer up to 5 billion cubic metres of water annually from the Yangtze river, to feed the inland river systems further north, including the Yellow river basin.³² The Chinese Meteorological Administration (CMA) has already installed more than 500 ground-based generators to seed clouds over the Qinghai-Tibetan Plateau.³³ The generators are activated by satellites that monitor and forecast meteorological conditions,³⁴ with further support announced in September 2022.³⁵ This experiment is intended to be scaled up to tens of thousands of generators, covering an area of up to 1.6 million km².³⁶ However, because of the controversial nature of the project, information on the Sky River project is scarce.³⁷

There are doubts that the scale of the Sky River project is feasible,³⁸ but more pressing are concerns that enhancing precipitation over the Himalayas for the benefit of China may deprive India of beneficial rainwater.³⁹ The project has been planned with little transparency or cooperation with neighbouring countries in South and Southeast Asia, especially India.⁴⁰ These factors contribute to discomfort over what is perceived by some to be the militarization of the Chinese weather modification programme.⁴¹

The rapid upscaling of China's capacity to intervene in atmospheric processes underscores the need for robust laws to assess and mitigate environmental impacts across provincial and international borders. The WMO notes that ‘legal aspects may be particularly important when weather modification activities are performed in the proximity of borders between different countries’.⁴² This article investigates these issues. It examines the way in which China currently governs its weather modification programme, with a particular focus on whether its current assessment and monitoring requirements satisfy customary international law obligations to avoid transboundary harm. We show that detailed laws are in place to address the safety of weather modification operations, but that limited consideration has been given to the risks of transboundary environmental impacts. The analysis is based on a review of available literature, combined with doctrinal analysis of officially translated Chinese laws, as well as policies and plans translated using translation software.⁴³

The analysis proceeds in six parts. Following this introduction, Section 2 outlines the development and features of China's weather modification programme. Section 3 considers China's international law obligations, with a particular focus on obligations to assess and prevent transboundary impacts under international customary law. Section 4 then evaluates whether the domestic regime governing weather modification activities meets China's international obligations to India and other neighbouring countries. Section 5 discusses the kinds of mechanism needed to ensure that China's weather modification laws comply with international requirements. We conclude in Section 6 that stronger safeguards are needed to address the environmental, social, and economic risks associated with weather modification, both within China and across national borders.

2. CHINA'S WEATHER MODIFICATION PROGRAMME

China is the largest investor in weather modification deployment globally.⁴⁴ Since 2014, governments at all levels in China have invested 13.267 billion yuan (CN¥) (or close to US$ 2 billion) in weather modification activities, including about US$ 400 million originating from the central government.⁴⁵ These activities have covered more than one third of China's total land area.⁴⁶ Atmospheric water resources are unevenly distributed across the country, with the south generally having more atmospheric water than the north, leading to varying cloud seeding potential in different regions.⁴⁷ Cloud seeding demand also varies depending on seasons, with most regions facing water scarcity in spring and summer, and a few regions facing limitations in autumn and winter.⁴⁸ While the number of research programmes is small,⁴⁹ most weather modification activities are conducted on an operational basis, using cloud seeding techniques for precipitation enhancement and hail suppression.⁵⁰ Both cloud seeding applications involve the dispersal of silver iodide, although dry ice and liquid nitrogen can also be used to enhance precipitation.⁵¹

Weather modification is a manifestation of China's attempts to harness atmospheric water resources to ensure economic stability, alongside commitments to ‘fix the air’ by addressing atmospheric pollution.⁵² The 2022 drought is the latest of many meteorological disasters in China, and the use of weather modification to mitigate heatwaves is only one application of the Chinese programme. Over the past two decades, China has deployed cloud seeding principally to increase freshwater resources and mitigate the impacts of hailstorms on weather-dependent sectors such as agriculture.⁵³

The possibility of weather modification was first championed by Mao Zedong in 1956, with a research programme entitled ‘Prior Research on Cloud and Precipitation Physics and Artificial Rain’.⁵⁴ The first weather modification experiments were conducted in 1958 in northern and western China.⁵⁵ China's extensive research on weather modification continued for over 40 years, before operational planning commenced with the establishment of the National Coordination Committee of Weather Modification⁵⁶ and the first Weather Modification Development Plan (1996–2010).⁵⁷ The 2012 State Council's ‘Comments on Further Strengthening Weather Modification’ (known as Document No. 44) provided the legal basis for the next Weather Modification Development Plan (WMDP) 2014–20.⁵⁸

The size, rapid up-scaling and breadth of weather modification in China is unprecedented.⁵⁹ As in other countries,⁶⁰ China uses weather modification to secure water resources for freshwater consumption and hydro-electric production, especially along the Yangtze river in Yunnan and Sichuan provinces.⁶¹ Weather modification, employed for both precipitation enhancement and hail suppression, is also used to increase food production and ensure food security, notably in the province of Jilin and the Yellow river plain.⁶²

Beyond these conventional applications, the technology has also been used for ecological restoration. For example, weather modification for precipitation enhancement has been conducted in the Sanjiangyuan National Nature Reserve in the province of Qinghai, to restore the headwaters of the Yangtze, Yellow and Mekong rivers.⁶³ The 2014–20 WMDP promotes weather modification as a tool to restore vulnerable ecological areas – such as rivers, lakes, glaciers and wetlands – which have been affected by climate change, desertification, and biodiversity loss.⁶⁴ It also claims that weather modification operations have increased the surface of lakes and grassland coverage in the Tibetan plateau, thus creating a ‘green ecological barrier’, which preserves those areas from economic development.⁶⁵ The Plan also promotes weather modification as a means to lower air temperatures during heatwaves, and lower surface water temperatures in lakes to control the proliferation of bacteria.⁶⁶

Cloud seeding can also improve air quality,⁶⁷ as increased rainfall ‘washes out’ harmful pollution from the air.⁶⁸ As part of its ‘blue skying’ campaign,⁶⁹ China uses weather modification to control sandstorms, reduce haze, and manage the health risks of air pollution. Weather modification has also been used to secure fair weather for important national events.⁷⁰ The 2008 Olympic Games is the best-known example of the government's assertion of control over atmospheric resources for public amenity.⁷¹ In response to the International Olympic Committee's threats to postpone the event because of the high level of air pollution,⁷² officials triggered rainfall to clean the air and prevent the heavy rainfalls forecast over Beijing.⁷³ China's use of weather modification for mega-events is only a minor aspect of the national weather modification programme,⁷⁴ despite it being mentioned frequently in the literature.⁷⁵ However, this demonstrates that China uses weather modification not only to adapt to climate change impacts, as is common in other countries, but to exert control over atmospheric resources, extending its influence beyond its territorial resources such as minerals and surface water.⁷⁶ Regardless of the purposes for which weather modification activities are conducted, there are risks associated with their deployment on such a large scale (for example, potential disruption of the hydrological cycle with effects on people and the environment).

The 2014–20 WMDP was issued to ensure the smooth development of weather modification technologies and bolster the management of weather modification.⁷⁷ While it provides a general summary of the potential environmental impacts of weather modification, the Plan nonetheless considers it beneficial for the country's sustainable development. The Plan integrates weather modification in the framework of ‘ecological civilization’, which broadly equates with the concept of ‘sustainable development’.⁷⁸ The 2014–20 WMDP identifies the main organizational challenges for weather modification, encompassing cross-regional operations, science-based decision making, security, and responsibility.⁷⁹ These challenges are especially pertinent in the context of multi-level and large-scale operations. The WMDP divides the country into six administrative regions – Northeast, Northwest, North, Central, Southwest and Southeast – as part of its commitment to strengthen ‘responsibility, information sharing, and coordination’ between state, province, city, and county levels.⁸⁰ Weather modification activities are conducted in all regions for different purposes, which include food, water, and ‘ecological’ security.⁸¹ In each region, one city is identified as the centre of operations and its meteorological bureau is responsible for coordinating cloud seeding operations at the regional level.⁸²

On completion of the 2014–20 WMDP, the Office of the State Council published its ‘Opinions on Promoting the High-Quality Development of Weather Modification’.⁸³ This document provided the foundation for the 2021–25 WMDP, and committed to strengthen research, innovation, and operational capacity for weather modification.⁸⁴ Between 2014 and 2020, weather modification activities for precipitation enhancement covered an area of 2.83 million km², with an estimated 79.2 billion tons of annual increase in rainfall and snowfall (or about 15% of the annual national water consumption).⁸⁵ Weather modification coverage is expected to double by 2025 under the 2021–25 WMDP to cover over 5.5 million km² for rainfall/snowfall enhancement, and 580,000 km² for hail suppression.⁸⁶ In total, these programmes will cover an area that is 150% larger than that of India.

Like the earlier Plans, the 2021–25 WMDP emphasizes the importance of weather modification for ecological restoration. This is in line with the Overall Plan for National Major Ecosystem Protection and Restoration Major Projects (2021–2035), which identifies key ecological areas, including the Qinghai-Tibet Plateau, and the Yellow and Yangtze rivers.⁸⁷ The 2021–25 WMDP encourages snow enhancement projects in the Himalayas to combat the retreat of the glaciers as a consequence of climate change.⁸⁸ The new WMDP also encourages the automation of weather modification delivery methods, especially the use of unmanned aerial vehicles (drones) and artificial intelligence.⁸⁹

Prominent scientists, such as Bruintjes, question China's unsubstantiated claims concerning the effectiveness of its weather modification activities.⁹⁰ Studies demonstrate that weather modification by cloud seeding is efficient only in the presence of clouds, and that operations conducted as an emergency response in times of drought are largely unsuccessful.⁹¹ Regardless of its effectiveness, the deployment of cloud seeding as an emergency response to the 2022 drought is the latest evidence of China's commitment to upscaling its national weather modification programme. The scale of its plans raises questions regarding the adequate management of environmental risks and associated socio-economic impacts.

3. CHINA'S OBLIGATIONS UNDER INTERNATIONAL LAW

This section introduces the international law applicable to weather modification activities. We explain why the Convention on the Prohibition of Military or Any Other Hostile Use of Environmental Modification Techniques (ENMOD Convention)⁹² is of limited use in providing safeguards for the peaceful use of weather modification, before focusing on the no-harm rule as the only rule of international law that imposes legal limits on China's weather modification programme.

3.1. The ENMOD Convention

The 1977 ENMOD Convention is the primary international instrument of direct relevance to weather modification.⁹³ It prohibits state parties from ‘engag[ing] in military or any other hostile use of environmental modification techniques having widespread, long-lasting or severe effects as the means of destruction, damage or injury to any other State Party’.⁹⁴ China acceded to the Convention in 2005.⁹⁵ However, the treaty establishes obligations concerning weather modification only for military or hostile purposes, while encouraging the use of weather modification for peaceful purposes, such as water management.⁹⁶ Article III(2) of the ENMOD Convention provides: ‘The States Parties to this Convention undertake to facilitate, and have the right to participate in, the fullest possible exchange of scientific and technological information on the use of environmental modification techniques for peaceful purposes’.⁹⁷ Apart from a broad commitment to facilitate exchange of scientific and technological information, the ENMOD Convention does not impose legal limits on China's use of weather modification for peaceful purposes.

For the Convention to apply, the hostile intent of a state needs to be demonstrated. While the term ‘hostile’ is not defined in the text or in the travaux préparatoires, the context in which the Convention was negotiated is crucial for understanding its scope. The ENMOD Convention originated with the 1974 Conference of the Committee on Disarmament.⁹⁸ The Preamble states that state parties were guided by ‘the cause of halting the arms race, and of bringing about general and complete disarmament under strict and effective international control, and of saving mankind from the danger of using new means of warfare’.⁹⁹ As confirmed during the first review conference, the ENMOD Convention is a multilateral disarmament convention, intended to prevent the development and use of technology for environmental – including meteorological – warfare.¹⁰⁰ It was not intended as an environmental agreement to manage (transboundary) environmental impacts. Initially intended to apply to situations of armed conflict, Bodle argues that ‘[a]pplying the ENMOD Convention in peacetime on the basis of a subjectively determined “hostile” use would erode this distinction and introduce a grey area between the two areas of law’.¹⁰¹ It is important, therefore, to distinguish between risks of transboundary harm from weather modification and the hostile use of these technologies. Conflating the two does not accurately reflect the scope and purpose of this Convention, and there is no state practice or decision of international courts or tribunals to support such an interpretation.

We acknowledge concerns regarding the potential future militarization of the Chinese weather modification programme. However, as long as China continues to conduct its weather modification programme for peaceful purposes, it does so in compliance with the ENMOD Convention. While the provisions of this Convention may become relevant in future, China's present execution of its weather modification programme falls outside the scope of the Convention.

3.2. The No-Harm Rule

The ‘no-harm rule’ is a fundamental principle of customary international environmental law. Originating from the Trail Smelter arbitration (1938–1941),¹⁰² the no-harm rule imposes a due diligence obligation on states to prevent activities within their jurisdiction and control that cause significant transboundary harm to the territory of other states and areas beyond national jurisdiction.¹⁰³ The no-harm rule has been affirmed in multiple decisions by international courts and tribunals.¹⁰⁴ It has also been re-articulated in Principle 21 of the Stockholm Declaration,¹⁰⁵ Principle 2 of the Rio Declaration,¹⁰⁶ and in numerous multilateral environmental agreements.¹⁰⁷ As a principle of customary international law, the no-harm rule is legally binding on all states and can be enforced through international litigation. Examples of situations in which states have invoked this rule include transboundary air pollution from smelters¹⁰⁸ and aerial herbicide spraying,¹⁰⁹ pollution of shared waterways,¹¹⁰ and the alteration of river flows.¹¹¹

The no-harm rule imposes substantive and procedural obligations on states for activities that pose a risk of ‘significant’ transboundary harm.¹¹² There is no objective definition of this threshold,¹¹³ but the International Law Commission (ILC) suggests that ‘significant’ means ‘something more than “detectable” but need not be at the level of “serious” or “substantial”’.¹¹⁴ As noted above, there is concern that China's weather modification activities could cause severe weather conditions hundreds of kilometres beyond the target area, and may either deprive neighbouring states of rainfall or cause flooding. Such risks are not trivial and would be likely to satisfy the Commission's threshold.

The no-harm rule is generally interpreted as providing states with a substantive ‘due diligence’ obligation, in that states must use ‘all means at their disposal’ to avoid significant transboundary harm occurring, but are not required to prevent it absolutely.¹¹⁵ The standard of care required to discharge this obligation depends on the activity in question. The care must be ‘appropriate and proportional to the degree of risk of transboundary harm’,¹¹⁶ with riskier activities attracting a higher standard of care. There are no international law cases involving weather modification that specify the type of action that is necessary, but the International Court of Justice (ICJ) has noted that risks of environmental harm are often irreversible and therefore warrant a more stringent standard of care.¹¹⁷ The ILC Draft Articles on Prevention of Transboundary Harm also suggest that the size and location of an activity, special climate conditions, and materials used should also be considered in determining the standard of care.¹¹⁸ The size of China's weather modification programme and its proximity to national borders would probably justify a high standard of care. The submission by Colombia in the Aerial Spraying judgment provides examples of the types of action that might be required, such as ensuring the use of the most up-to-date technology and methods, ensuring environmental monitoring, ongoing scientific review of the programme, and independent auditing of the programme.¹¹⁹

To satisfy their due diligence obligation under the no-harm rule, states must also take appropriate regulatory and administrative action to address the risk of transboundary harm.¹²⁰ The ICJ made clear in its 2010 Pulp Mills judgment that this entails the adoption and vigilant enforcement of appropriate rules and measures under domestic law.¹²¹ Those rules should adopt or give effect to a precautionary approach, in that states cannot use scientific uncertainty regarding the precise nature of risks as an excuse to ignore their obligations under customary international law.¹²² Adopting a precautionary approach is especially relevant for activities like weather modification, where there might be ‘plausible indications’ of potential transboundary risks but uncertainty concerning their scope or nature.¹²³ In such situations, Boyle suggests that the precautionary approach may indeed ‘reduce the standard of proof required in order to establish that an activity poses a risk of harm’.¹²⁴ In other words, the precautionary principle implies that states still have obligations under the no-harm rule where there is a risk of serious or irreversible transboundary harm, but there is uncertainty as to its precise nature or magnitude.

If triggered, the no-harm rule also imposes procedural obligations on states: namely, the duty to conduct a transboundary environmental impact assessment (EIA),¹²⁵ the duty to cooperate, and a duty to notify and consult with potentially affected states.¹²⁶ In its Pulp Mills judgment, the ICJ affirmed the duty to conduct a transboundary EIA as a principle of customary international law in its own right, as well as a necessary component of due diligence.¹²⁷ Customary international law does not dictate the precise content and scope of a transboundary EIA, but the ICJ has noted that it should reflect the ‘nature and magnitude of the proposed development and its likely adverse impact on the environment’.¹²⁸

Several international organizations have recommended that states conduct weather modification activities in line with the no-harm rule and have further clarified what states should do to satisfy their international legal obligations. In 1980, the United Nations Environmental Programme (UNEP) developed the Provisions on the Cooperation of States in Weather Modification.¹²⁹ These provisions explicitly extend general principles of international law, including the no-harm rule, to weather modification activities, stating that ‘weather modification activities should be conducted in a manner designed to ensure that they do not cause damage to the environment of other States or of areas beyond the limits of national jurisdiction’.¹³⁰ They recommend that states assess the environmental consequences of weather modification activities ‘which are likely to have an effect on areas outside of their national jurisdiction’ and ‘make the results of such assessments available to all concerned States’.¹³¹ They also recognize that states have obligations of cooperation, consultation, notification and exchange of information concerning weather modification activities that present transboundary risks.¹³² The UNEP Provisions recommend that states gather and record information on weather modification to make it available to the WMO,¹³³ and invite states to ‘encourage and facilitate international cooperation’ through bilateral, regional or multilateral agreements.¹³⁴

In 2018, the ILC finalized its Draft Guidelines on the Protection of the Atmosphere, which provide that ‘intentional large-scale modification of the atmosphere should be conducted with prudence and caution, subject to any applicable rules of international law’.¹³⁵ This further suggests that states should comply with the no-harm rule when conducting large-scale weather modification activities. Therefore, to satisfy its obligations, China would need to conduct transboundary EIAs of weather modification activities, as well as notify and consult with neighbouring states that may be adversely affected by these activities.

4. THE DOMESTIC LEGAL FRAMEWORK FOR WEATHER MODIFICATION IN CHINA

This section examines the domestic legal regime governing weather modification in China. An understanding of this framework is necessary to evaluate China's compliance with international customary law, particularly the obligation to prevent transboundary harm (further discussed in Section 5).

4.1. Institutional Arrangements

China's current framework focuses on the beneficial impacts of weather modification for local communities and ecosystems. The Meteorology Law 1999 lays the legal foundation for Chinese weather modification projects and policies in its Chapter V ‘Prevention of Meteorological Disasters’.¹³⁶ The law defines weather modification as:

efforts aimed at rain or snow enhancement, hail suppression, rain suppression, fog dispersal, frost prevention by exerting, under appropriate conditions, artificial influence on local atmospheric, physical and chemical processes through scientific and technological means, in order to avert or mitigate meteorological disasters and rationally exploit climatic resources.¹³⁷

This definition extends beyond the mere avoidance of weather disasters to the exploitation of climatic resources. The Regulations on Meteorological Services 1994, which the Meteorology Law replaced, defined climatic resources as ‘climate conditions such as solar, thermal, hydraulic and wind energy which can be used in human economic activities’.¹³⁸ However, the current Meteorology Law does not define ‘climatic resources’. While the reasons behind this omission are unclear, Chen and Cui explain that ‘[o]ne reason might have been to preserve the flexibility to expand the scope of the definition whenever technological advances facilitate the exploitation of new forms of climate resources’, including the exploitation of atmospheric water via weather modification.¹³⁹ The lack of definition may give the law a wider scope, but it also creates uncertainty regarding the type of activity to which the Law might apply.

Under Article 30 of the Meteorology Law, governments at all levels are authorized to plan and organize weather modification.¹⁴⁰ It also provides competent meteorological departments with authority to administer, guide and arrange weather modification operations.¹⁴¹ At the national level, the CMA Department of Emergency Response, Disaster Mitigation and Public Services coordinates weather modification activities, supervises the work of local meteorological departments, and organizes research through nine meteorological institutes.¹⁴² Article 30 also outlines the obligations that bodies engaging in weather modification activities must satisfy: these include having appropriate qualifications, using specified equipment, and following any operational rules.¹⁴³ Under Article 39, violations of Article 30 requirements incur sanctions ranging from injunctions and disciplinary warnings to fines of up to CN¥100,000 (or about US$ 20,000).¹⁴⁴ Compensation is payable if weather modification conducted in breach of Article 30 causes loss to others.¹⁴⁵ However, the Law does not create compensation mechanisms for loss caused by weather modification activities conducted in compliance with Article 30. It is also unclear whether such compensation could be paid to foreign nationals – or neighbouring countries – adversely affected by the activities.

The State Council adopted the Regulations on Administration of Weather Modification in 2002 ‘for the purpose of strengthening the administration of weather modification, and preparing against and mitigating meteorological disasters’.¹⁴⁶ The regulations recognize that weather modification plans prepared by local meteorological departments and approved by governments are for ‘public welfare’ and expenses included in governments’ budgets.¹⁴⁷ Under the regulations, local governments are responsible for organizing experts to evaluate the effects of weather modification.¹⁴⁸ The regulations also require the exchange of information between relevant departments, including meteorological stations and departments in charge of agriculture, water conservancy, and forestry.¹⁴⁹ However, nothing in the law or the regulations provides for exchange of information with foreign counterparts regarding activities conducted in the proximity of international borders.

Most responsibilities lie with the meteorological departments. The meteorological departments of provinces, autonomous regions, or municipalities (that is, at the subnational level) have the authority to determine the most suitable sites for weather modification operations,¹⁵⁰ define qualification requirements,¹⁵¹ and organize training and examination of personnel engaged in weather modification.¹⁵² As at 2014, close to 48,000 people were employed in weather modification activities¹⁵³ and thus required training under the regulations.¹⁵⁴ In addition, the meteorological departments at or above county (local) levels are responsible for ensuring the safety of operations, including through public notification of weather modification operations.¹⁵⁵ As Gasser explains:

The national, regional and provincial levels are mainly responsible for the implementation of weather modification projects involving aircraft operations, the city, county and station level on the other hand, are responsible for the execution of ground operations with rockets and cannons.¹⁵⁶

Regional Weather Modification Centres coordinate weather modification at the regional level.¹⁵⁷ The CMA established the Weather Modification Centre in 2007,¹⁵⁸ but it was only officially launched by the Communist Party's Central Committee and the State Council in 2021.¹⁵⁹ The CMA Weather Modification Centre coordinates weather modification operations across the six weather modification regions (for example, cross-regional operations) and participates in the development of national weather modification plans and guidelines.¹⁶⁰ For instance, the Weather Modification Centre has developed a system of real-time communication – the National Air-Ground Communication System – which allows for the rapid exchange of information in air-based weather modification operations.¹⁶¹ Despite these technological advances, information on weather modification activities is not systematically made accessible to other states or the WMO.

The regulations also stipulate safety standards for equipment. They require that weather modification equipment, including rockets and rocket launchers, be manufactured according to national technical standards and requirements.¹⁶² These materials must be transported and stored in accordance with laws related to the administration of weaponry and explosives,¹⁶³ and must be verified annually.¹⁶⁴ It is an offence to use equipment that fails to meet these safety standards,¹⁶⁵ and individuals and organizations responsible for causing serious accidents in violation of the regulations may be held civilly or criminally liable.¹⁶⁶

Despite this extensive framework governing the administrative and safety aspects of weather modification, the regulations do not provide for impact assessment of weather modification operations. Instead, this falls within the scope of China's general environmental legislation.

4.2. Environmental Impact Assessment of Weather Modification

The Law on Environmental Impact Assessment of the People's Republic of China 2002 (EIA Law) (amended in 2016 and 2018) requires relevant departments at all levels to prepare EIAs for both plans and construction projects.¹⁶⁷ While ‘plans’ and ‘construction projects’ are not defined, weather modification activities fall within the scope of the EIA Law in so far as they require the construction of delivery apparatus, such as installation of ground generators. The 2014–20 WMDP required EIAs for specific weather modification projects (‘construction projects’), in recognition that increased rainfall would ‘provide ecological water for larger areas through natural water system and water conservancy facilities’ but would also ‘directly affect local ecosystems’.¹⁶⁸ No separate EIA was needed for the Weather Modification Development Plans, as Article 18 of the EIA Law prevents the duplication of EIA requirements.¹⁶⁹

All construction projects must undergo some form of assessment, but different requirements apply depending on the likelihood of a project causing significant impacts.¹⁷⁰ Article 16 of the EIA Law provides that ‘[i]f the environmental impacts may be significant, [the construction entities] shall work out a report of environmental impacts so as to include an all-round appraisal of the environmental impacts’.¹⁷¹ Accordingly, the competent meteorological bureau in each of China's six weather modification regions was required to prepare comprehensive environmental impact statements (EIS) for their weather modification construction projects. The EIS must contain an environmental baseline study, an evaluation of the potential environmental impacts and protection measures, a cost-benefit analysis, suggestions for environmental monitoring, and an overall assessment of whether a project should proceed.¹⁷² In recent years, China has consolidated its EIA system to remedy deficiencies.¹⁷³ However, the multiplicity of amendments and technical guidelines has rendered the system complex, fragmented, and unpredictable. Issues of local government accountability, enforcement, and public participation remain.¹⁷⁴

The EIA legislation makes access to information and public participation mandatory, unless the state deems the project to be confidential.¹⁷⁵ Some regions have already conducted and published EISs for their weather modification projects.¹⁷⁶ In most cases, the proponent is required to solicit comments from both experts and the public, and to specify which comments have been considered when finalizing the EIS.¹⁷⁷ However, the EIS for the Southwest region, in which the Sky River project is located, is confidential and not publicly available.

While the Chinese central government has progressively formalized public participation in environmental decision making,¹⁷⁸ local authorities have been able to select their preferred participation mechanisms (such as expert meetings or solicitations of opinion).¹⁷⁹ Some local officials have carried out participation processes formalistically.¹⁸⁰ Questionnaires are the main method of public participation, rather than public hearings or meetings. This technique has significant drawbacks.¹⁸¹ Pre-defined questions can be complex, selected participants are not always representative of affected communities, and the acceptance or rejection of comments is often poorly justified.¹⁸² Accordingly, commentators have suggested that China's efforts to increase participation in EIA has been ineffective in practice.¹⁸³

The agency responsible for assessing impacts also varies with the size of the proposed project. Under the EIA Law, an EIS must be examined and approved by ‘the competent administrative department in charge of environmental protection’.¹⁸⁴ Reforms have devolved approval powers to provincial and county-level environmental protection bureaus to streamline EIA procedures and improve efficiency.¹⁸⁵ However, the national Ministry of Ecology and Environment remains responsible for reviewing and approving the EIS for construction projects ‘that include different provinces, autonomous regions or municipalities directly under the Central Government’.¹⁸⁶ This is notably the case for regional weather modification projects that are cross-boundary in nature. Nevertheless, the EIA Law does not require consideration of potential transboundary impacts.

The Chinese EIA framework does not require or provide for participation by the public located outside China. However, this omission is not unique to the Chinese context, and unsurprising given that there is no regional framework for cooperation on EIA in Asia.¹⁸⁷ Boyle suggests that denying equal access to information, participation, and effective remedies to people affected extraterritorially could amount to a human rights violation.¹⁸⁸ However, there is no such requirement under international customary law, which requires ‘state’ participation, rather than public participation.¹⁸⁹

The Northwestern region is the largest weather modification region, covering an area of about 3.53 million km².¹⁹⁰ Its EIS was the first to be published in 2016,¹⁹¹ providing insights into some of the limitations of EIA approaches in the context of weather modification. The Northwestern EIS considered pollution resulting from the construction phase of the project (2016–2019), focusing on dust, noise, water pollution, and solid waste.¹⁹² It concluded that these would not have significant environmental impacts after appropriate mitigation actions.¹⁹³ The EIS also addressed the environmental impacts of the weather modification operations themselves,¹⁹⁴ stating that operations were expected to use 208 kilograms of silver iodide each year.¹⁹⁵ The assessors noted the low toxicity of silver iodide and concluded that the operations would not have significant environmental impact because the potential concentrations were far below the National Standard for Drinking Water Health Standards (≤0.05 mg/L (milligrams per litre)).¹⁹⁶ However, the EIS did not consider the overall amount of silver iodide used countrywide because EIA procedures in China (as in many countries) focus on the direct impacts of a proposed activity, and do not require consideration of indirect or cumulative impacts and interactions.¹⁹⁷

The Northwestern EIS completed two stages of public participation. Following online publicity and onsite public notices, the CMA solicited public opinion through a questionnaire (rather than a public hearing). According to the EIS, 96.8% of those contacted responded to the questionnaire.¹⁹⁸ No one expressed opposition to the proposed project,¹⁹⁹ although 62.8% of participants responded that they had only a slight understanding of weather modification.²⁰⁰ This experience reflects a limitation of the EIS process in China: that participation procedures can be (and often are) designed to comply with minimum legal requirements, rather than facilitate meaningful public consultation.²⁰¹ Indeed, ‘top-down’ participation mechanisms, such as questionnaires, are often conducted after decisions are reached, casting serious doubt on their influence in decision making.²⁰² This approach to EIA is also consistent with what has been referred to as ‘authoritarian environmentalism’, where ‘[p]ublic participation is limited to a narrow cadre of scientific and technocratic elites while others are expected to participate only in state-led mobilisation for the purposes of implementation’.²⁰³

The Northwestern EIS acknowledged that rain enhancement operations would have impacts on surface water but concluded that the impacts on nearby nature reserves would be positive.²⁰⁴ These nature reserves constitute natural habitat for species protected under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)²⁰⁵ and bilateral agreements on migratory birds;²⁰⁶ thus, supporting the ecological health of these areas is consistent with international obligations.

The Northwestern EIS did address the issue of potential extra-area effects. It recognized that weather modification would be likely to increase overall precipitation over non-target areas by 1%, equivalent to approximately 60 billion tons of water, without changing its temporal and spatial distribution.²⁰⁷ Concerning the risks of impacts beyond China's borders, the EIS explained that, because weather systems essentially move from west to east across China, the expected increase in rainfall would mostly affect the Chinese territory.²⁰⁸ The Northwestern EIA process did not require or include any consultation or cooperation with adjacent countries, nor with countries along the Mekong-Lancang river, which originates in the Northwest region (Qinghai). To comply with due diligence obligations, China's EIA processes need to incorporate a more thorough consideration of transboundary impacts, including through enhanced transparency and granting neighbouring countries access to relevant information.

The lack of transboundary EIA requirements and consultation with potentially affected states under Chinese domestic law is concerning, given the scale of current weather modification projects and their proximity to neighbouring states. Moreover, this gap has not been filled by any ‘extraordinary’ processes of consultation with neighbours, such as India. This raises questions about China's compliance with its due diligence obligations under customary international law.

4.3. Ownership of Atmospheric Resources

China has developed a robust legal framework to govern the safety aspects of weather modification, but questions remain about its ability to address the governance and ownership of atmospheric water. Under the Constitution, the central government owns natural resources, including water resources.²⁰⁹ China's Water Law 2002 confirms that ‘water resources are owned by the State’,²¹⁰ but the Water Law explicitly applies to surface water and groundwater and does not clarify the legal status of atmospheric water. The Meteorology Law delegates the management of climatic resources, including atmospheric water, to lower levels of government.²¹¹

In line with the Meteorology Law, several provinces have asserted state ownership of climatic resources. In 2012, the Northeastern province of Heilongjiang became the first to pass Regulations on Climate Resources Survey and Protection, recognizing state ownership over climatic resources.²¹² The regulations define climatic resources as ‘wind energy, solar energy, precipitation and any component of the atmosphere that is capable of being used by human activities’.²¹³ Shanxi, Guangxi, Guizhou, and Tibet have all passed similar regulations.²¹⁴ While several Chinese commentators have criticized the constitutionality of these provincial regulations, Chen and Cui argue that the nationalization of climatic resources is consistent with Chinese law.²¹⁵ Chen also argues that, even though state property is often used as a means to expand governmental control over resources, it is also an optimal property regime for emerging natural resources, such as atmospheric water.²¹⁶ It facilitates future transition in utilization patterns and creates room for flexibility in the face of scientific uncertainty.²¹⁷

Chien, Hong and Lin suggest a tension between the provisions of the Water Law and the Meteorology Law which could result in jurisdictional conflicts between the central and local governments.²¹⁸ They argue that the ownership of water resulting from weather modification activities in the Henan and Hubei provinces, which affect catchment areas that supply the Greater Beijing region, is uncertain.²¹⁹ It is unclear whether these provinces exclusively own the water or if they are under an obligation to share with cities in other provinces, including Beijing. The Regulations on Administration of Weather Modification 2002 contain provisions intended to avoid disputes between local governments over so-called ‘cloud theft’. They establish specific procedures for weather modification operations implemented across the boundaries of provinces, autonomous regions or municipalities, requiring relevant governments to consult with neighbouring areas over cross-boundary decision making.²²⁰ Where governments cannot agree, the CMA is empowered to decide.²²¹ However, there are no provisions in the regulations or elsewhere under Chinese law that require consultation with neighbouring states that might be affected by China's weather modification activities.

5. ENHANCING CHINESE WEATHER MODIFICATION LAW TO ADDRESS TRANSBOUNDARY EFFECTS

Concerns over the Chinese weather modification programme are taking place against a backdrop of diplomatic and military tensions over the disputed Himalayan border, known as the Line of Actual Control. It extends over 3,500 km between India and China. The tensions escalated in June 2020, with confrontations in the Galwan valley, resulting in the loss of military personnel on both sides.²²² These tensions had already affected hydrological data sharing in 2017. China failed to share data on the Brahmaputra river following a stand-off in the Doklam region, which compromised India's flood control and disaster management capacity.²²³ Adding to controversies relating to China's construction of dams upstream of transboundary rivers,²²⁴ China's use of weather modification to control water resources in the Himalayas is challenging water security in the region.²²⁵

There are also growing concerns over the potential militarization of China's weather modification programme.²²⁶ The prospect of weather modification being used for military purposes prompted the development of the ENMOD Convention,²²⁷ to which China is a party. The geopolitical implications of the Chinese weather modification programme suggest that international mechanisms may be needed to improve state cooperation and regulate large-scale weather modification. Such an approach was suggested by the ILC in its report on protection of the atmosphere.²²⁸

China has contributed actively to international initiatives on meteorological sciences.²²⁹ This demonstrates a level of commitment to cooperation with the international scientific community. However, given the large scale of China's weather modification activities and the proximity to state borders in which some activities are being conducted, scientific cooperation alone cannot satisfy China's obligations under the no-harm rule.²³⁰ As noted above, China also has an obligation to adopt appropriate rules and measures at the domestic level to prevent transboundary harm.²³¹ However, China's domestic laws for weather modification do not currently fulfil the procedural obligations required under the no-harm rule relating to impact assessment, consultation, and notification. Rather than conducting transboundary EIAs, notification and consultation on an ad hoc basis, China should develop mechanisms under its domestic law to ensure routine practice and adherence by weather modification operators.

If China fails to implement such measures, there are limited options available to neighbouring states under international law. As noted in Section 3, breaches of the no-harm rule have been the subject of international litigation, the most recent example being the Certain Activities and Construction of a Road cases between Costa Rica and Nicaragua.²³² In order for such a claim to proceed, however, China would need to consent to have it brought before an international court or tribunal. Alternatively, neighbouring states in Southeast Asia could seek to negotiate a new regional or multilateral agreement with China and each other. Such an agreement could facilitate consultation with countries likely to be affected by weather modification,²³³ but the likelihood of such an agreement seems low. China has been reluctant to join international agreements regulating the management of transboundary rivers.²³⁴ It has entered into regional agreements to facilitate transboundary cooperation over shared water resources with some of its neighbours, such as Russia.²³⁵ However, the practice of transboundary EIA in China is still in its infancy. At the minimum, setting up an information-sharing platform could ensure greater transparency in the conduct of weather modification activities. As Knowles and Skidmore argue, ‘[a]s China invests substantial funding into programs that are likely to cause ripple effects across multiple economies, both transparency and quality analysis are in the interests of the global community’.²³⁶

Another potential forum for cooperation is the WMO. This organization has long played a leading role in facilitating information exchange on weather modification through joint research projects,²³⁷ international training and dialogue,²³⁸ and the creation of a voluntary reporting mechanism.²³⁹ The WMO terminated its reporting system in 2007 and instead established the Expert Team on Weather Modification Research to keep relevant research under review, provide advice and assistance to states on scientific experiments, and develop guidelines on the status of weather modification.²⁴⁰ China participates in meetings of the Expert Team, contributes to its trust fund, and organizes WMO training on weather modification.²⁴¹ Until 2001, China also regularly reported its weather modification activities to the WMO Register on National Weather Modification Projects. Given the limitations of China's domestic arrangements and regional agreements, other states (including states in the region) could use the WMO forum to formalize cooperation. Re-establishing the voluntary reporting mechanism is one option, although a mandatory reporting mechanism would be more effective in avoiding the risk of transboundary effects.²⁴²

6. CONCLUSION

A growing number of states are using weather modification as a climate adaptation measure,²⁴³ but the scale of China's weather modification programme is unprecedented. The scale of the Sky River project is significant in its own right, and some critics have suggested that China's weather modification programme could provide the infrastructure needed for more controversial global solar radiation management (SRM), such as stratospheric aerosol injection.²⁴⁴ It is currently unlikely that China would deploy SRM unilaterally,²⁴⁵ but its weather modification programme does demonstrate the country's willingness and capability to undertake large-scale atmospheric intervention projects.²⁴⁶ China is involved in SRM research, but Chinese scientists contend that China will not proceed with SRM deployment until international collaboration mechanisms are in place.²⁴⁷ Weather modification and SRM are often distinguished on the basis that weather modification is intended to modify weather events at the local scale, whereas SRM typically contemplates intervention in the climate system at the global scale.²⁴⁸ The line is blurred for regional programmes,²⁴⁹ and the magnitude of the Chinese weather modification programme raises questions concerning the value of such distinction.²⁵⁰ In this article we have argued that China should apply greater caution in respect of large-scale weather modification.

The Chinese government has developed a strong legal framework to govern the safety aspects of weather modification, showcasing the government's purported control over atmospheric resources. However, the governance of weather modification in China does not fully address potential environmental impacts associated with the scale of its programme, especially the risk of transboundary impacts. For China to comply with international customary law, a revision of its domestic legal framework is needed to reflect both the substantive and procedural obligations imposed under the no-harm principle.

Firstly, China should strengthen its legal framework to perform greater ‘due diligence’ in preventing its national weather modification programme from causing significant transboundary harm, and give effect to a precautionary approach. This is especially important for projects such as the Sky River project, which take place close to the boundary with neighbouring states. Secondly, China should adopt and enforce appropriate procedural measures to address the risk of transboundary harm. China could create clear processes for conducting transboundary EIA under the existing domestic framework. This would include assessment and monitoring of impacts on regional rainfall distribution and transboundary watercourses. China would also need be more proactive in fulfilling its duty to cooperate with, notify, and consult with potentially affected states, starting with greater transparency in sharing assessment and monitoring results. Such measures could address the environmental and socio-economic risks associated with weather modification, both within and across national borders, and reduce regional geopolitical tensions.

A multilateral regional instrument could address deficiencies in China's domestic governance of large-scale atmospheric interventions. Such an instrument could encourage notification and consultation with potentially affected countries and assessment of transboundary risks. It could also establish a mechanism for information sharing on weather and climate intervention research and development. In the absence of such an agreement, however, the WMO has an important role to play in strengthening international cooperation and information exchange. In the meantime, China will need to revise its domestic framework to align with principles of customary international law, potentially setting an example for other states to follow.