So the Earth warms a few degrees before the end of the century; so what. The Earth has adapted to dramatic climate changes over the billion-years course of its existence; in all likelihood it will adapt again. However, from the immediate and human perspective, these are three of the innumerable reasons that humans of the early twenty-first century could justify drastically curbing the continued accumulation of atmospheric greenhouse gases.
With pollution, habitat degradation and other human-caused conditions already compromising their resiliency, many marine species will be challenged to adapt to climate-change induced rising water temperatures and alterations in the oceans’ chemical cycling. Fisheries’ abundance and distribution will shift, affecting the availability of seafood for consumption and the revenue of fish-dependent economies. From a study published in the journal Nature, the following chart presents a broad synopsis of the likely effects of climate change on global fisheries.
Surprise! Another feedback cycle to calculate in climate change projections:
Rapidly rising temperatures in northern latitudes are accelerating the thawing of permafrost. Ground thawed for the first time in eons is releasing greenhouse gases from decayed plants that have been frozen and trapped for tens of thousands of years. This new source of greenhouse gases accelerates warming, which speeds the melting of permafrost, which releases more gases and amplifies warming … It is a feedback cycle largely overlooked in climate change projections.
Permafrost Carbon Research Network scientists estimate that previously permanently frozen ground up to 10 feet deep could soften and thaw, becoming a bigger factor in the global warming equation than the cutting of forests. Authors of a report issued in Nature calculate that the released gases would increase the speed of warming 20 to 30 percent above the rate produced by fossil fuel emissions alone. Analysis of the network’s findings suggest that global warming is likely to be worse than expected, according to Jay Zwally, a NASA polar scientist who wasn’t part of the study.
More heat + less water = reduced yields: how will the world respond?
For years scientists have expressed concern over the long-term effects a warmerclimate would have on the water cycle – on seasonal rains and snow-pack melt and water-table levels – and the consequences of such change on the world’s agricultural production. But crop researchers at American universities are saying that high temperatures themselves pose a danger, disrupting botanical processes such as pollination and shrinking the output of many crops and vegetables.
According to Gerald Nelson, an economist with the International Food Policy Research Institute, “With temperatures rising, we are going to have trouble maintaining the yields of crops that we already have.” It is estimated that for every one degree Celsius that temperature rises above a grain crop’s optimum, yield declines by 10 percent.
As climate change increasingly affects food security, food, in the words of Lester Brown, founder and president of the Earth Policy Institute, becomes the hidden driver of world politics. Brown cites twin causes of food insecurity: population growth and climate change. He advocates integrating world agricultural policy with energy, population and water policies and cautions, “ If we cannot produce higher crop yields with less water and conserve fertile soils, many agricultural areas will cease to be viable … If we cannot move at wartime speed to stabilize the climate, we may not be able to avoid runaway food prices. If we cannot accelerate the shift to smaller families and stabilize the world population sooner rather than later, the ranks of the hungry will almost certainly continue to expand. The time to act is now …”