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.
The report does conclude with high confidence risks to low-lying coastal areas: emergencies during extreme weather, mortality from heat, food insecurity, loss of livelihood in rural areas due to water shortage and temperature increases, loss of coastal ecosystems and livelihoods that depend on them, and loss of freshwater ecosystems. But again, this high confidence comes with an absence of quantification of how many/much and the degree of risk. Will extreme weather double, triple, or quadruple the number of extreme emergency weather-related events of a given magnitude (dollars or lives lost)? Will it increase these incidences by 10 percent, or will some areas face increased risk while other areas face reduced risk?
In the end, the report is a compendium of things that might happen or are likely to happen to someone or something, somewhere. But what does this actually mean for me, or anyone who might read the report? I would avoid beachfront property. If my livelihood depended on a coastal resource, I would try to find a different job, or at least urge my children to pursue another line of work.
That is where a measure of wealth brings some resilience—I have those options, others do not. The report “quantifies” in some sense by establishing an element of “relative risk,” concluding that the poor and marginalized in society are more vulnerable because they do not have the means to adapt. Beyond this, it is not clear that climate prediction is at a high enough level to offer information that I can use to take concrete actions for most day-to-day decisions and investments.
What the report does provide is some documentation of adaptation in action—what different regions, cities, sectors, and groups are doing to adapt—concluding that there is a growing body of experience from which to learn.
However, perhaps the greatest truth in the report is in the following statement:
“Adaptation is place and context specific, with no single approach for reducing risks appropriate across all settings (high confidence). Effective risk reduction and adaptation strategies consider the dynamics of vulnerability and exposure and their linkages with socioeconomic processes, sustainable development, and climate change.”
Hence, while it’s possible to learn from others’ adaptation experiences, in the end, the specifics of climate change in my place, given my circumstances, and the socio-economic environment in which I live will present me with very different climate outcomes and opportunities to adapt than you will have where you live.
This fact alone raises the cost of adaptation, because to some degree each recipe needs to be invented anew. What worked in the past likely won’t work in the future—or at least, not as well. And we need to process a lot of highly uncertain climate projections in developing the new recipe.
The report also concludes, not surprisingly, that risks increase and extend to more people, places, and things if the global temperature rise is three degrees Celsius or greater than if there is only a one-degree rise. Overall, the report provides, in my judgment, a compelling case for more serious mitigation efforts—the topic of the next IPCC report, to come out later this month.
John Reilly is the co-director of the MIT Joint Program on the Science and Policy of Global Change.