Will climate chaos reign in the Anthropocene?
“Far from being self-stabilizing, the Earth’s climate system is an ornery beast which overreacts even to small nudges.”
| “Human civilization developed during the Holocene (the past 12,000 years). It has been warm enough to keep ice sheets off North America and Europe, but cool enough for ice sheets to remain on Greenland and Antarctica. With rapid warming of 0.6°C in the past 30 years, global temperature is at its warmest level in the Holocene. … Earth’s paleoclimatic record tells us that atmospheric greenhouse gases are now near the dangerous level where tipping points become unavoidable.” –James Hansen [1] |
To judge by many accounts of climate change, the twenty-first century will gradually become a warmer, stormier, and less biodiverse version of the twentieth. There’s an unspoken assumption that the Anthropocene will be less pleasant than the Holocene, but not fundamentally different, and that the transition will be smooth. As research commissioned by the U.S. National Research Council points out, that assumption leads to particular conclusions about society’s ability to respond to change:
“Many projections of future climatic conditions have predicted steadily changing conditions giving the impression that communities have time to gradually adapt, for example, by adopting new agricultural practices to maintain productivity in hotter and drier conditions, or by organizing the relocation of coastal communities as sea level rises.”
But the authors emphasize that the actual experience could be very different:
“The scientific community has been paying increasing attention to the possibility that at least some changes will be abrupt, perhaps crossing a threshold or ‘tipping point’ to change so quickly that there will be little time to react. This concern is reasonable because such abrupt changes – which can occur over periods as short as decades, or even years – have been a natural part of the climate system throughout Earth’s history. The paleoclimate record – information on past climate gathered from sources such as fossils, sediment cores, and ice cores – contains ample evidence of abrupt changes in Earth’s ancient past, including sudden changes in ocean and air circulation, or abrupt extreme extinction events.” [2]
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