The European Union Emissions Trading System (EU ETS) is the largest mandatory programme of its kind. The entitlements in emissions allowances (emissions entitlements) combine public and private law characteristics: allowances are tradable, commercially valuable regulatory instruments. This dual nature reveals a new interdependency between public and private law mechanisms in the context of climate change policy. This article argues that achieving the requisite level of emissions reductions is contingent on the viability of the emissions market, and that both are dependent on the definition of emissions entitlements. This view is supported by a case study which identifies the practical and serious consequences of the absence of a legal concept of emissions entitlements. The United States (US) Acid Rain Program offers useful lessons on the treatment of emissions entitlements. They can be further defined by analogy with similar rights regimes. Their nature is highly relevant to the emissions market, particularly to the commercial contracts that constitute it.

Leontopodium is a genus of approximately 30 species with a conspicuous Asian–European disjunct distribution. In this study samples from the Himalayan/Tibetan centre of diversity of the genus, as well as from Europe, were analysed to infer a phylogeny of the genus using sequences of nuclear ribosomal (ITS and ETS) and plastid (matK and trnL/F) DNA. The Southeast Tibetan monotypic Sinoleontopodium [Leontopodium lingianum (Y.L.Chen) Dickoré, comb. nov.] falls into Leontopodium. Monophyly of Leontopodium, including Sinoleontopodium, is supported. Due to low rates of sequence divergence, intrageneric relationships in general are weakly supported, a pattern frequently observed in plant groups centred in the Tibetan Plateau. Three phylogenetic groups can be identified, however, and these are also supported by morphology. The low levels of nucleotide divergence suggest a young age for the group, which has been influenced by the turbulent geological history of the Tibetan Plateau. Leontopodium is a characteristic Sino-Himalayan element that appears to have found its way into the mountains of Europe in geologically recent times. The two European taxa, Leontopodium alpinum and L. nivale, form a genetically distinct group, which, considering the wide geographic disjunction, shows surprisingly little divergence from its Asian relatives.