Implications for Biodiversity of Potentially Committed Global Climate Change (from Science and Policy)

Abstract

Climate change impacts on biodiversity that are observed today are substantially less than those predictable in the future. Vital policy-relevant information regarding global climate change and biodiversity includes the sources of increased future global warming commitment, which stem from both climate change policy and climate science. Full, long-term (over many 100s of years) equilibrium global warming commitment, calculated by the constant atmospheric greenhouse gas composition, is put at ‘about 2 °C’ by the IPCC 2014 assessment. Significant further committed warming at 2 °C is expected due to weakened terrestrial carbon sinks and large planetary sources of carbon feedback emissions. Committed climate change due to policy is calculated from national emissions targets. Together these policy targets lead to over 3 °C global warming by 2100, which will increase much more after 2100. Commitment clearly shows the climate, oceans and biodiversity global emergency, requiring the immediate decline of emissions with supporting responses that are well known and universally recommended.