WASHINGTON — The risk posed to mankind and the environment by even small changes in average global temperatures is much higher than believed even a few years ago, a study said Monday. Published by the Proceedings of the National Academy of Sciences, the study updated a 2001 assessment by the Inter-governmental Panel on Climate Change that looked at temperature changes and the risks they pose. ‘Today, we have to assume that the risks of negative impacts of climate change on humans and nature are larger than just a few years ago,’ said Hans-Martin Fussel, one of the authors of the report. The new study found that even small changes of global mean temperatures could produce the kinds of conditions singled out as ‘reasons for concern’ in the 2001 assessment. Those included risks to threatened systems such as coral reefs or endangered species; and extreme weather events like cyclones, heat waves or droughts. Other ‘reasons for concern’ involved the way the impact of climate change is distributed, the aggregate damage caused and the risk of ‘large scale discontinuities’ such as the deglaciation of the Greenland ice sheets. ‘Compared with results reported in the (2001 assessment), […]