Climate change is causing measurable harm to natural and human systems, according to the most recent scientific assessment published by the Intergovernmental Panel on Climate Change (IPCC). The world is already witnessing effects on “agriculture, human health, ecosystems on land and in the oceans, water supplies, and some people’s livelihoods.” The current concentration of carbon dioxide in Earth’s atmosphere means human populations will be seeing these effects for the foreseeable future, and investment in adaptation measures will be necessary to prevent catastrophic levels of harm.  

The findings in Climate Change 2014: Impacts, Adaptation, and Vulnerability represent the consensus view of a United Nations-organized group of scientists, compiled as part of the IPCC’s Fifth Assessment Report (AR5). The publication of Climate Change 2014 follows the October 2013 release of the physical science basis (which I wrote about here). These two parts, taken together with the forthcoming report on mitigation, will encapsulate the broadest, most rigorous assessment of the state of the climate, its impact on our daily lives, and the best methods we have for reversing its effects and surviving its damage.

The report makes for sobering reading. According to the extant literature, we are seeing a pattern of rising negative impacts on crop yields, even taking into account how climate change may improve the growing seasons in some areas (where colder climates are now mild enough to support longer growing seasons). Further, the IPCC finds that global governments exhibit, in the aggregate, “a significant lack of preparedness for current climate vulnerability.” The effect is most profound on already poor communities, who often lack the safety net necessary to survive price volatility in agriculture, or the destruction of vital infrastructure (including homes) during extreme weather events.

The prospective good news is that human ingenuity is starting to catch up to the dire situation. Global governments are beginning to realize the necessity of planning for and investing in measures to make communities more robust in the face of these negative impacts. Unfortunately, the sheer complexity of human economic systems, and the long-range time frame over which climate change effects occur, mean that humans have an imperfect understanding of our own adaptation needs.

In assessing risk, the IPCC is particularly focused on the effects of storm surges, coastal flooding, and sea-level rise, and how they may disrupt economic and social life in low-lying areas, particularly in cities, given recent trends toward increased urbanization. Conversely, the lack of water in many regions experiencing warming trends will negatively impact agricultural communities, especially in the developing world.  Pervasive food insecurity risks, among other factors, will drag down economic growth, and reduce much of the antipoverty gains of the late twentieth century. Human health indicators may also suffer as a result of more widespread severe heat conditions and drought.

Even the field of armed conflict will not escape from the reaches of a climate-volatile world. The IPCC forecasts an increase in human migration, which, in addition to shocks to economic and political systems, may aggravate existing tensions and perhaps contribute the likelihood of new ones. Climate change will thus necessitate renewed efforts at building multilateral institutions to prevent armed conflict.

What’s the way out? As the IPCC makes clear, if emissions are contributing to climate change-induced risk, the obvious solution is to reduce emissions, beginning as soon as possible. While some climate change is already “locked-in” (due to historic emissions activity), aggressive action on emissions will drastically reduce our risk. The simplest, most efficient way to place us on this pathway would be to place a price on carbon (either through a tax, as the Canadian province of British Columbia uses, or a cap-and-trade system, used by California and the European Union). Human behavior responds to incentives, and such a disincentive to emit carbon would help set us on the right path (especially if some of the tax revenue were earmarked for clean energy investment).

In the meantime, for governments worldwide, a focus on infrastructure, housing, and provision of basic services will allow communities to more easily withstand negative effects. Economic diversification, so areas are not dependent on one type of economic activity, would likely protect livelihoods from climate-related threats.  Concerned governments and the local, regional, and national level may need to create new financing and insurance mechanisms to insulate communities against economic catastrophe in the event of severe weather, whether it is a Superstorm Sandy or a pervasive drought.

More controversially, the report estimates that a rigorous response to the effects of climate change may require the developed world to shift as much as $100 billion per year in aid to the developing world. While the IPCC cites that figure in the larger report, it was omitted from the Summary for Policymakers, according to reports by Justin Gillis in the New York Times (by virtue of its brevity, the Summary for Policymakers will likely be the only part of the report that is widely read).  

The impact of climate change is already being felt around the globe, and the worst is yet to come. As the IPCC report states, though, we have the know-how and means at our disposal to protect ourselves; what is missing is the will to make expensive investments now to deter future impacts.