At the end of March, the Intergovernmental Panel on Climate Change (IPCC) will release the Fifth Assessment Report from Working Group II on Climate Change: Impacts, Vulnerability and Adaptation. The WGII report will look at what climate change means for ecosystems and society. What are the observed impacts of climate change? What is projected to happen under different scenarios of climate change? What are the implications for oceans, cities, food systems, health, human security, poverty and livelihoods? How can humans and other species adapt to these changes, and what are the limits to adaptation as an effective response? What are the implications for different regions of the world? Importantly, what are the prospects for climate-resilient pathways for sustainable development? This is the report for anyone asking the question “climate change, so what”?
Understanding the “so what?” of climate change is critical to decision-makers of every type. Although the conclusions of the report will not be finalized until the end of UN plenary session in Yokohama, Japan, on March 29, 2014, it is possible to anticipate some of the content that will be in the report by considering some of the major patterns and trends that have emerged from over decades of climate change research. The Fifth Assessment Report will provide valuable information on the following seven trends:
1) More and more observed impacts of climate change are being documented, both for nature and society. These are not just related to climate change extremes, but also to gradual changes, such as the melting of glaciers and permafrost, changes in species distributions, earlier springs, and so on. How do we know that these observed changes are related to climate change, rather than part of natural variability? The science of detection and attribution looks at the likelihood of these occurring in the absence of human influence. It is important to recognize that climate change is a process, not an event, and that our measure of “climate” is statistical rather than “real” – it is an average of measurements. Many of the observed impacts are related to social trends, including more people living in vulnerable areas. The AR5 report will assess the knowledge to date on what these impacts are, where they are happening, and who is affected.
2) The impacts are not distributed evenly across society. Some regions, groups, sectors, or countries are experiencing negative impacts of the increase of 0.85°C in globally averaged temperatures (from 1880-2012) calculated by Working Group I, whereas others may not experience or perceive the impacts. The definition of “dangerous” climate change depends on who you are, where you are, and how you can cope with and adapt to multiple shocks and stressors. Climate change is not the only change taking place in the world today, but we know that a drought can make it harder to recover from an economic crisis, just as an economic crisis can make it harder to recover from a drought. The AR5 report will look at these distributional effects of climate change, including the implications for human security, poverty and livelihoods.
3) The impacts are not occurring linearly over time. What we are seeing instead is that the greater the warming, the greater the risks associated with impacts. The impacts from 0 to 1°C or 1°C to 2°C of warming is not the same as the impacts associated with an increase from 3°C to 4°C. This is because the impacts are systemic, with new links and feedbacks showing up as temperatures of the atmosphere and oceans increase. For example, as temperatures rise, lakes warm and more water evaporates; some species thrive, others do not and there is a greater human demand for water, both for municipal uses and irrigation. Together, these will introduce new social and ecological impacts as warming continues. Twenty years ago, many researchers expected the impacts of climate change to appear gradually, in a linear manner. We see this is not the case, and nowhere is this more clear than in the Arctic. The AR5 will investigate how impacts evolve according to different emissions scenarios of climate change.
4) Adaptation is becoming increasingly important as the impacts of climate change become more visible. Whereas very few researchers and decision-makers were talking about adaptation in the early 1990s, now it is receiving attention at every level, and within most sectors of society. There are still many questions about adaptation, both about the technical details (i.e., adapting to what and how) and about the social process (e.g., who decides and who pays). There are also uncertainties about the limits to adaptation – at what point will we simply have to face losses. One can think of the loss of snow and its implications for the economy, ecology and culture. It may be possible to adapt to some of the economic impacts, but the disappearance of snow may represent significant loss to many. The AR5 will present an assessment of the current understanding of adaptation, adaptive capacity, the constraints and limits, and the costs.
5) The costs of climate change impacts and adaptation are uncertain, but not trivial. Attempts have been made to estimate the annual costs as a percentage of GDP, but over the past decades have seen that the economic and human costs of climate-related disasters is increasing, often because more people and assets are exposed. It is hard to come up with numbers, especially because many of the costs are not tangible – experiences, opportunities and places that are, according to many, priceless. Whether we are talking about glaciers or corals, islands or deltas, the things that are valued by humans are at risk. The AR5 report will discuss different valuation methods, recognizing that the simple cost-benefit approach is insufficient.
6) The consequences of climate change are both local and global, with effects spreading through production, trade, migration, financial markets and travel. Fifteen to twenty years ago there were a number of “country studies” on climate change impacts, vulnerability and adaptation. In a globalized economy, we see that the impacts in “far-away” places have widespread consequences. Production chains are distributed across the globe, as are investments. The Norwegian Pension Fund, the largest pension fund in the world, has investments in businesses and real estate around the world, including in the American Water Company in California. The AR5 will include 10 chapters that highlight the regional consequences of climate change – for example, on North America, Europe, Asia, Africa and Central and South America, so that one can start to understand the significance of these connections.
7) We have learned over the past decades that choices are important. The decisions or choices made in the past have had a strong influence on the present situation, and this includes when we have decided by default not to do something, or not take action. Choices and decisions about development, mitigation, sustainability, adaptation, and disaster risk management influence the outcomes that we experience today, and this will be even moreso in the future. The choices and decisions society makes today—what we invest in now and what we decide to avoid investing in now — will influence the type of world that we live in fifty and two hundred years from now. The AR5 will provide information that can help us to make choices now that will put us on the path to a climate-resilient future.
The 30 chapters of the IPCC Fifth Assessment Report from Working Group II add details to some of the patterns and trends that have been emerging for decades. Together, they tell an important story about the potential of present generations to influence the future. It is a story where the risks are high and outcomes uncertain, but also one where humans are the protagonists who can potentially save the day.