The difficulty of predicting local effects of climate change makes a compelling case for preventing it.
This week the Intergovernmental Panel on Climate Change (IPCC) released a major report focused on what actions might or could be taken to adapt to climate change. It attempts to describe who and what is especially vulnerable to climate change, and gives an overview of ways some are adapting.
The report makes clear that specific estimates of how climate change will affect places, people, and things are very uncertain. Brought down to a local level, climate change could go in either direction—there are risks that a given area could get drier or wetter, or suffer floods or droughts, or both. This uncertainty makes efforts to prevent climate change even more important.
Specific risks to natural systems are well documented by the report. It finds, for example, the greatest risks are to those ecosystems, people, and things in low-lying coastal areas, because expected sea-level changes are in only one direction, up. This is also the case in the Arctic, where the temperature rise is expected to be much greater than the global average. There is good science and unanimous agreement among climate models behind these assertions.
But a frustrating aspect of the report—and a reflection of the difficulty of working in this line of research—is that very few specific risks to humans are quantified in a meaningful way. For example, one might ask: has my risk of death increased because of more hot days? The report says, “Local changes in temperature and rainfall have altered the distribution of some water-borne illnesses and disease vectors (medium confidence).” This seems to state the obvious, while giving no indication of whether the alterations may have increased or decreased risk or what the magnitude of the alteration might be. Given that the statement seems to say little, it is hard to imagine there is not high confidence.
MIT Technology Review (the report):
Why We Can't Just Adapt to Climate Change, John Reilly
MIT Joint Program on the Science and Policy of Global Change
NOLA Times Picayune: Hurricane Katrina
FEMA: Hurricane Sandy Recovery
What Climate Change Means for Africa, Asia and the Coastal Poor