What are the limits to climate change adaptation?

In the absence of decisive action to significantly cut the emission of earth-warming greenhouse gases, most poor countries have resigned themselves to adapting to the effects of climate change. But as recent data show, the global concentration of carbon dioxide in the atmosphere hit 400 parts per million - something that has not happened in the last million years, and possibly not in the last 25 million years, according to a National Aeronautics and Space Administration scientist - leading to the questions: do even we know what we are adapting to, and what are the limits to our adaptation?

A recent paper published in Nature Climate Change points out that many communities are already facing limits to their capacity to adapt. They suggest the development of a framework to define and identify these limits, both for individuals and for communities.

One of the paper’s six authors, Richard Klein, a senior researcher at the Stockholm Environment Institute and an author of the Intergovernmental Panel on Climate Change reports, explained in an email to IRIN, "For example, a farmer may no longer be able to grow enough food to sustain his or her family (e.g., due to saltwater intrusion or recurring droughts) and decide to give up farming and move to the city to become an informal worker. On the one hand, that's a form of adaptation, but from the perspective of the farmer, who would have preferred to keep farming, a limit has been reached. But from the perspective of the community or the country, food security may not be at risk so no limit has been reached.”

Knowing the extent to which an individual, community or country can adapt will be critical for policymakers, including those charting a country’s agricultural path and those planning for urban growth.

Yet little is known about the limits of adaptation. “It's intuitive that the existence of limits should have policy implications, but the challenge is that, even though we know that limits are real, our ability to predict them is very small indeed,” said Klein.

Defining limits

The authors suggest a risk-based approach to define these limits and a framework to identify them.

"It's intuitive that the existence of limits should have policy implications, but the challenge is that, even though we know that limits are real, our ability to predict them is very small indeed"

“Limits to adaptation are a function of both the rate and magnitude of climate change, and adaptive capacity,” wrote Klein. “Limits are also scale-dependent; they could refer to individual farmers or households, to communities, to sectors, to countries, and so on.”

The authors propose defining an “adaptation limit as a point at which an actor can no longer secure valued objectives from intolerable risk through adaptive action.”

They offer rice farming as an example. South Asian rice plants' ability to pollinate and flower peaks at 26 degrees Celsius; there is a 10 percent decline in yield for every one degree Celsius above that. Here, the “adaptation limit” is the inability to breed rice varieties that pollinate at all above 32 to 35 degrees Celsius. The “valued objective” is to produce rice as a staple crop and for export. The “intolerable risk is a level of loss in rice production, farmer livelihoods, income from exports and food security. Rising temperatures increase the future probability that rice harvests may fail.”

If this adaptation limit is reached, alternative sources of affordable rice will have to be found for consumers, and rice farmers will have to grow other crops to compensate for the loss of income.

Preparing for hardships

Collective efforts to adapt will likely be a complex process, as the authors point out the tolerable degree of risk varies from individual to individual. The best policies would better manage change before the capacity to adapt is exhausted.

But much more must be learned before appropriate policies can be developed. The authors underscore the urgent need for research in key areas - including agriculture, water resources management and disease control - “to determine where limits may exist so that actors may anticipate and plan to mediate the hardships that cannot be avoided.”

They suggest a focus on strengthening early warning systems within countries and communities and improving the capacity to operate across the various scales - from individuals to sectors - as the impact of climate change unfolds.