While the parties to the UNFCCC agreed in the December 2009 Copenhagen Accord that a 2°C global warming over pre-industrial levels should be avoided, current commitments on greenhouse gas emissions reductions from these same parties will lead to a 50 : 50 chance of warming greater than 3.5°C. Here, we evaluate the differences in impacts and adaptation issues for water resources in worlds corresponding to the policy objective (+2°C) and possible reality (+4°C). We simulate the differences in impacts on surface run-off and water resource availability using a global hydrological model driven by ensembles of climate models with global temperature increases of 2°C and 4°C. We combine these with UN-based population growth scenarios to explore the relative importance of population change and climate change for water availability. We find that the projected changes in global surface run-off from the ensemble show an increase in spatial coherence and magnitude for a +4°C world compared with a +2°C one. In a +2°C world, population growth in most large river basins tends to override climate change as a driver of water stress, while in a +4°C world, climate change becomes more dominant, even compensating for population effects where climate change increases run-off. However, in some basins where climate change has positive effects, the seasonality of surface run-off becomes increasingly amplified in a +4°C climate.<\/p>\n
Fung, F., Lopez, A., and New, M. January 2011. Water availability in +2ºC and +4ºC worlds.<\/em> Philosophical Transactions of the Royal Society A, v.369 (1934), pp.99-116.<\/p>\n\n","protected":false},"excerpt":{"rendered":"\n Abstract While the parties to the UNFCCC agreed in the December 2009 Copenhagen Accord that a 2°C global warming over…<\/p>\n\n","protected":false},"author":43,"featured_media":0,"template":"","tags":[670],"publication-type":[436],"topic_area":[],"class_list":["post-3129","publication","type-publication","status-publish","hentry","tag-water-resource-management","publication-type-research-articles"],"acf":{"downloads":{"ref_value":"field_52f16cc1a80f2","value":false,"type":"repeater","post_type":""},"profile_link":{"ref_value":"field_52f164b5189e9","value":["water-availability-in-2oc-and-4oc-worlds"],"type":"relationship","post_type":""},"article_link":{"ref_value":"field_52eee3c7f0586","value":"","type":false,"post_type":""},"article_link_title":{"ref_value":"field_5322399d89d42","value":"","type":false,"post_type":""},"spotlight":{"ref_value":"field_52f80896506d3","value":"","type":false,"post_type":""},"exclude_from_sync":{"ref_value":"field_560538b0e7350","value":"0","type":false,"post_type":""},"rss_newsletter":{"ref_value":"field_54f5c2c1544d8","value":"","type":false,"post_type":""}},"yoast_head":"\n