Latest IPCC report highlights need for integrated climate/human behavior models

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"We need to continue discovering how the Earth system works in order to evaluate the numerous ways that humans can adapt to climate change," says Kevin Noone, IGBP's executive director. The additional challenge is to model unpredictable human behaviour and merge this into deterministic Earth system models, explains Noone.

Human adaptation to a changing climate can take many forms, and can have both positive and negative environmental impacts. Small-scale measures could include increased use of air conditioning, architectural changes for more efficient heating and cooling, better forecasting and warning systems for extreme events, and increased water usage. Larger-scale issues could vary from switching to renewable energy sources to attempts at "geoengineering". The large-scale movement of people away from areas adversely affected by climate change and by other environmental and socioeconomic stresses is also a form of adaptation. Each of these options has environmental consequences that must be carefully evaluated before they are implemented. The larger the adaptation scheme, the greater care needs to be taken in considering its application.

"The science needed to support decision making about adaptation requires a sophisticated understanding about how the Earth system works, but goes well beyond just that. We need new tools to help us develop robust "what if" scenarios for different potential adaptation schemes, and their consequences," says Noone. He describes the new tools as new types of models that couple together active, predictive descriptions of human behaviour and choice with the kinds of models used to predict future climate.

Another fundamental issue about adaptation schemes is whether they will contribute to an increase or decrease in equity across the globe. The predictions recently released by the IPCC WG2 show that in many cases the areas facing the largest changes in climate are not only located in countries that have contributed the least to the atmospheric buildup of greenhouse gases, but also those that have the least ability to adapt to them. "One way or another, we will adapt to a changing climate," says Noone. "Adaptation always involves trade-offs. The question is what level of justice and equity we want to build into how we adapt. We still need to build up the kind of basic research linking social and natural science that can be used to provide sound support for decisions about adaptation."

Researchers from IGBP's network of Earth system scientists who authored chapters of the IPCC WG2 report have this to say about adaptation to climate change:

Patricia Romero-Lankao, IPCC WG2 Coordinating Lead Author Chapter 7, "Industry, Settlement and Society" (Deputy Director, Institute for the Study of Society and Environment, National Center for Atmospheric Research): "The underlying conclusion of Chapter 7 is that none of us will escape the impacts of a warming planet. In many cases, global warming will interact with other environmental problems (e.g., deforestation, water scarcity) and make them worse. People in developing countries will be hardest hit by climate change. But as hurricane Katrina and the 2003 heat wave in Europe have showed us, that does not mean that people in the wealthiest countries will be spared."

Tony McMichael, IPCC WG2 Review Editor Chapter 8, "Human Health" (Director, National Centre for Epidemiology and Population Health, Australian National University and Co-Chair, Global Environmental Change and Human Health project of the Earth System Science Partnership): "I welcome the growing emphasis on the modeling of adaptive strategies to lessen the health risks. Recent evidence from extreme heat waves, cyclones and droughts has shown how widely the health impacts vary between old and young, rich and poor, and those with strong versus weak social institutions and supports. Human societies and communities are very varied in resources, culture and behaviour. Stronger linkages between natural and social sciences are now essential if we are to develop realistic integrated models that connect projected climatic change, social change and human vulnerability."

Steve Running, IPCC WG2 Lead Author Chapter 14, "North America" (Professor, Department of Ecosystem Sciences, University of Montana): "For the last twenty years Earth scientists have concentrated on building predictive models of first the physical climate, followed by the integrated biogeochemistry of the planet. Unfortunately, these models operate implicitly as if humans did not exist. The new challenge is to build Earth Systems models that incorporate human policy options, economic preferences, and decision making that can then feed back to influence the biophysical states of the system. The increase in model complexity and interdisciplinary requirements is daunting."

Karen O'Brien, IPCC WG2 Lead Author Chapter 17, "Assessment of Adaptation Practices, Options, Constraints and Capacity" (Associate Professor, Department of Sociology and Human Geography, University of Oslo and Chair, Global Environmental Change and Human Security project of the International Human Dimensions Programme on Global Environmental Change): "Climate change adaptation has both equity and ethical dimensions. It is important to recognize that one person, group or nation's adaptation to climate change may lead to the increased vulnerability of others; this will be especially evident in relation to water access and usage. Modeling these dynamics will be a challenge that requires input from both the biophysical and social sciences."

"Adaptation is a social process that is influenced by differential interests, values, preferences, priorities, resources and power. All of these factors may change in response to ongoing societal transformations, thus the capacity to adapt to climate change can be considered highly dynamic. The way that society adapts to a changing climate has widespread implications for human security."

Gary Yohe, IPCC WG2 Coordinating Lead Author Chapter 20, "Perspectives on Climate Change and Sustainability" (Woodhouse/Sysco Professor of Economics, Wesleyan University): "The WG2 Report calls for adopting a risk management perspective in assessing impacts, adaptation, and sustainable development. Indeed, risk-based portraits of impacts—net of the effects of alternative adaptations—can, when inserted into alternative development pathways at specific locations, offer decision-makers insight into climate risks calibrated in many different metrics (such as millions at risk of hunger or water stress in addition to economic damages)."

"When also cast into the context of alternative mitigation strategies informed by science that describes the full range of possible futures, these portraits can clearly display one of the fundamental conclusions of WG2: adaptation and mitigation will both be required to cope with climate change over the short and long terms."

"Moreover, we now know that these two broad categories of policy options are complementary tools in a policy portfolio designed to reduce climate risk by reducing exposure (through mitigation) and reducing sensitivity to climate impacts (through adaptation)."

International Geosphere-Biosphere Programme