Adaptation. For many in the climate change community, the word has had a traitorous ring, implying that its proponents were giving up on the notion that the world might mitigate the threat of global warming by significantly reducing emissions of greenhouse gases. Adaptation was for quitters.
With nations in the industrialized and developing worlds continuing to pump record levels of carbon dioxide into the atmosphere, hopes are fading that over the next half-century atmospheric CO2 levels can be kept below 450 parts per million (ppm) and global warming held to 2 degrees Celsius (3.6 Fahrenheit). Now, a new sense of urgency has arisen as to how the world will adapt to a warming planet, where carbon dioxide levels could hit 600 parts per million and global temperatures could rise by 3 to 4 degrees C (5.4 to 7.2 degrees F).
“My view is that we’ll be lucky if we can stop CO2 at 600 ppm,” says Wallace Broecker, a geoscientist at Columbia University’s Earth Institute. “There’s no way we’re going to stop at 450. Impossible. If we’re going to double CO2, we’d better prepare what we’re going to do about it.”
If Broecker and many of his fellow climate scientists are right, the planet will experience myriad far-reaching changes to which humans, plants and animals will need to adapt: higher sea levels, the melting of glaciers that have long supplied hundreds of millions of people with water, drought-stressed agriculture, more severe storms, spreading disease, and reduced biodiversity.
“We’re talking about altering the world’s biogeography,” says Neil Adger, of the Tyndall Centre for Climate Change Research at the U.K.’s University of East Anglia and lead author of the Intergovernmental Panel on Climate Change (IPCC) Assessment of adaptation. “In extreme weather events, coastal flooding, wildfires, and droughts, the world is recognizing that predicted impacts are already happening.”
Major international organizations and governing bodies — including the European Union, the World Bank, and the IPCC — have called for the
Last year, the John D. and Catherine T. MacArthur Foundation announced that it was committing $50 million to conservation groups to help them preserve biodiversity in eight ecologically rich “hotspots” as the world warms.
Stanford University climatologist Stephen Schneider points out that adaptation strategies are only beginning to be developed, mainly because there’s precious little science on adaptation and few working models.
“Everyone is now talking about adaptation, but for all the talk there’s little actually being done,” says Schneider.
Developing strategies to cope with the impacts of a warmer world will be complex and expensive. Oxfam estimates it could cost some $40 billion a year; the World Bank estimates it might cost more than three times that. While strategies and technologies designed to mitigate climate change can be applied globally — one less coal-powered plant in China has the same effect as one less plant in the U.S. — adaptation strategies must deal with regional and local geography.
In April, for example, a European Union report on adaptation said Europe’s most vulnerable regions to climate change will be southern
Climate change will test not only the resiliency of ecosystems but also the adaptability of cities, villages, and societies.Europe, the Mediterranean basin, the Alps, and the far north. Europe will have to adapt to the diminishing Alpine glaciers that now provide 40 percent of its fresh water. Africa, the western U.S., and Australia will have to adapt to intense droughts. Communities in the Arctic will have to adapt to melting ice and permafrost. If the Himalayan region loses its glaciers and monsoon patterns change, 40 percent of the world’s population will likely face severe shortages of water for drinking and agriculture.
To preserve ecosystems and endangered species, conservationists will have to adapt their strategies. And epidemiologists will have to adapt to changing disease vectors. Climate change will test not only the resiliency of ecosystems but also the adaptability of individual cities, villages, and societies.
CONFRONTING WATER SCARCITYIn the world’s sub-tropics, most models predict that wet regions will become wetter and dry regions drier, but there’s little agreement on how these trends will affect regional annual rainfall patterns and growing seasons. And it’s these that determine crop productivity. Farmers have always had to adapt to changing weather patterns. Climate change will exacerbate the uncertainties, both in the short and longterm. The key to coping will be to make farming as resilient as possible.
Researchers in Ethiopia, for example, found that many farmers had already recognized that temperature and precipitation changes were affecting their crops and altering the growing season. Once they were given access to technical support, credit, and information about future climate change, these farmers adjusted their agricultural practices. They changed crop varieties, adopted soil and water conservation measures, and changed planting and harvesting periods.
For researchers at the Rockefeller Foundation, future “simultaneous changes in temperature, precipitation, CO2 fertilization, and pest/pathogen dynamics” will require breeding new crop varieties, especially for those crops that feed most of the world’s poor. The reserve of genetic material now in seed banks may not be enough from which to develop new drought-, temperature-, or flood-resistant crops, and the foundation is urging new efforts to increase the world’s genetic reserves of seed crops.
Adaptation strategies are already underway to cope with changes in the world’s fresh water resources. In April, the European Union issued a dire warning about declining water resources. Temperatures in the Alps — “the water tower of Europe” — have increased 1.5Â°C (2.7Â°F) over the last 100 years, twice the global average. The glaciers are vanishing. At the same time, warming temperatures and drought have left southern Europe dry, with creeping desertification in Spain and Portugal. The EU is focusing on adaptation strategies aimed mainly at reducing demand through water conservation, introducing new methods of efficient irrigation, and reforming water pricing.
RISING SEA LEVELSWhile scientists still debate predictions of sea level rise over the century due to climate change — with many studies predicting an increase of one to two meters — there is no doubt that rising seas have already begun affecting low-lying coastal regions. How humans adapt will depend not only upon regional geography, but regional development. The world’s large river deltas — the Mississippi, Nile, Rhine and Ganges — have been altered by development and agriculture, their tidal wetlands diminished and, with that, their resistance to flooding and erosion weakened, especially during storm surges.
That is why in the Ganges-Brahmaputra delta in Bangladesh, efforts are
By 2030, some 60 percent of the world’s population will live in flood-prone coastal areas.underway to restore lost mangroves to keep storm surges from flooding agricultural land and human settlements, and to keep delta land from washing away. At the same time, Bangladesh is trying to restore its upland forests to prevent downstream erosion. Islands, too, will hope to adapt to rising seas by creating or restoring natural buffer zones.
Things will be different, however, where coastal nature has already been lost to population growth and development.
By 2030, some 60 percent of the world’s population will live in coastal cities that may be increasingly subject to flooding from storm surges. Complex and expensive solutions will be needed to protect not only homes and people, but sanitation, communication, and transportation infrastructures. New York City, where the land is only 5 to 16 feet above sea level, has engaged a consortium of city agencies and researchers from Columbia University’s Earth Institute to develop adaptation plans to deal with sea level rises that could easily reach 1 Â½ feet by 2080, as well as with increased tidal and storm surges.
City planners are modeling the risks and working with New York citizens’ groups and city agencies to develop a coordinated approach to protecting vulnerable roads, tunnels, water supplies, transit, sewers, and water treatment plants. One firm has proposed a concrete tidal barrier that would stretch across the neck of lower New York Bay, similar to one that the Russian government has already commissioned to protect St. Petersburg from rising levels of the Baltic Sea.
THE SPREAD OF DISEASEThe greatest impediment to developing adaptation strategies to deal with the expected increase in disease due to climate change, is that “the regions with the greatest burden of climate-sensitive diseases are also the regions with the lowest capacity to adapt to the new risks,” writes Jonathan A. Patz of the Center for Sustainability and the Global Environment, Nelson Institute for Environmental Studies at the University of Wisconsin.
In these places, disease is most often the result of poverty, overpopulation, lack of access to fresh water, malnutrition, and lack of sanitary facilities, all of which will be exacerbated by global warming. One concern of scientists is the spread of disease-carrying mosquitoes and other insects as temperatures rise, a phenomenon already evident in parts of the world. Climate change may also cause clean water supplies to dry up in small villages, forcing residents to collect water from streams and ponds contaminated by insects and pathogens whose fecundity and range may well increase in a warmer world.
River flooding can also contaminate water supplies. Gambia, for example, has undertaken a program along the Gambia River coastal floodplain to increase the number of improved pit latrines in school, health and community centers; to purchase fogging machines and sprayers for insect control; and to stockpile drugs and vaccines to deal with disease outbreaks. In Samoa, authorities are developing a program in which doctors and meteorologists work together to predict outbreaks of disease — such as mosquito-transmitted dengue fever — that may worsen as temperatures rise.
PRESERVING BIODIVERSITYThe most localized adaptation strategies may be best suited to deal with the effects of climate change on the world’s biodiversity. As habitats and even seasons are altered, species will be forced to adapt or migrate in what — by
Early adaptation studies have been aimed at making people and places resilient to a possible range of changes.normal evolutionary standards — are very short time spans. They may follow expected adaptive pathways: Lowland species may move to higher elevations or migrate north, as some bird and plant species already are doing. In many places, however, migration routes are blocked by development or deforestation. Current nature reserve boundaries may no longer protect species forced by climate change to migrate. And while older trees that find themselves in an altered climate may survive, their seedlings may have a far narrower range of conditions under which they can thrive and thus be unable to grow in a warmer environment.
Enlarging the borders of established reserves will provide some species with protection while they seek out new ranges. Where reserves are hemmed in by developed land, efforts are underway to create wildlife corridors or preserve even small natural refuges — forests or wetlands — in the midst of cultivated fields. Such fragments of habitat may prove useful to birds or insects as their migration routes change.
As experts contemplate the challenges of climate change adaptation, they are stressing the need to proceed on sound scientific grounds. Without understanding the science, Schneider says, there’s every possibility of developing “maladaptations,” such as reacting to changes that appear to be caused by climate change, but that may be due to normal weather variables such, as El Nino, or to natural cyclical changes in species abundance.
For example, to implement irrigation after a few years of drought only to find that the longer-term forecast will be for a wetter — not drier — environment, is to waste a great deal of time, money, and good will. So would construction of a sea wall to protect against a mistaken prediction of sea level rise. Drought-resistant crops may be susceptible to new pests or diseases. That is why early adaptation studies have been aimed at understanding vulnerabilities, evaluating adaptive potential, and attempting to make people and places resilient to a possible range of changes.
Adaptation must also be finely tuned not only to the vagaries of local geography and ecology, but to local economies and cultures. Kate Barnes, climate program associate for the MacArthur Foundation, has found that cultural, economic, and political differences affect adaptation efforts to preserve the world’s montane biodiversity from the effects of climate change. In Bhutan, for instance, researchers found people’s “intrinsic appreciation for nature” made them more open to adaptation strategies than in Peru, where an interest in producing biofuels and gas exploration superseded an interest in conservation.
“The reality,” Adger says, “is that people don’t want to move and will resist adaptation when it affects things they care about — their jobs and their homes — even if they’re no longer sustainable.”