Environmental health risk assessment and management for global climate change
Thursday, 18 December 2014
This environmental health risk assessment and management approach for atmospheric greenhouse gas (GHG) pollution is based almost entirely on IPCC AR5 (2014) content, but the IPCC does not make recommendations. Large climate model uncertainties may be large environmental health risks. In accordance with environmental health risk management, we use the standard (IPCC-endorsed) formula of risk as the product of magnitude times probability, with an extremely high standard of precaution. Atmospheric GHG pollution, causing global warming, climate change and ocean acidification, is increasing as fast as ever. Time is of the essence to inform and make recommendations to governments and the public. While the 2ºC target is the only formally agreed-upon policy limit, for the most vulnerable nations, a 1.5ºC limit is being considered by the UNFCCC Secretariat. The Climate Action Network International (2014), representing civil society, recommends that the 1.5ºC limit be kept open and that emissions decline from 2015. James Hansen et al (2013) have argued that 1ºC is the danger limit. Taking into account committed global warming, its millennial duration, multiple large sources of amplifying climate feedbacks and multiple adverse impacts of global warming and climate change on crops, and population health impacts, all the IPCC AR5 scenarios carry extreme environmental health risks to large human populations and to the future of humanity as a whole. Our risk consideration finds that 2ºC carries high risks of many catastrophic impacts, that 1.5ºC carries high risks of many disastrous impacts, and that 1ºC is the danger limit. IPCC AR4 (2007) showed that emissions must be reversed by 2015 for a 2ºC warming limit. For the IPCC AR5 only the best-case scenario RCP2.6, is projected to stay under 2ºC by 2100 but the upper range is just above 2ºC. It calls for emissions to decline by 2020. We recommend that for catastrophic environmental health risk aversion, emissions decline from 2015 (CAN International 2014), and if policy makers are limited to the IPCC AR5 we recommend RCP2.6, with emissions declining by 2020.