This policy brief summarises the present state of knowledge on transboundary climate risks and discusses the implications for adaptation programming, policy and global governance. When a global food price crisis occurred in 2007-8, many countries experienced severe social and political unrest. Analysts offered explanations of the causes, which were myriad, including not just poor harvests linked to unusual weather, but also the collateral effects of response measures taken by countries to insulate their domestic markets from early price spikes (such as export bans and commodity hoarding).