We still cannot predict exactly how climate change will affect each part of the world, but the people on the front lines are showing others how to adapt
IT IS hard to prepare for a disaster, but harder still to prepare for a disaster that you can't identify. Yet that is the quandary facing many nations, which still don't know how climate change will affect them – even though it is already happening. That means many communities must prepare for the unknown.
We are running out of time to gather scientific evidence, says Koko Warner of the United Nations University (UNU) in Bonn, Germany. It is clear that climate change is happening, driven by human emissions of greenhouse gases, and its impacts will be felt around the world. But it has proved difficult to predict how events like floods and droughts will change in specific areas over the coming decades.
The second instalment of the latest Intergovernmental Panel on Climate Change report came out on Monday (see "World must adapt to unknown climate future, says IPCC"). In earlier IPCC reports, part two made regional predictions, to tell communities what will happen around them. But this year's report instead focuses on how people are, and should be, adapting to climate change.
"We cannot wait for climatologists to establish exactly what role climate change played in different events," says Kees van der Geest, also at UNU. "We want to build societies that are more protected against possible deterioration. We want to know why some things work, what doesn't work well, how we can improve, how we can make our society better prepared."
On a global level, the IPCC warns of a laundry list of calamities. We are told that cities will flood; farms will be hit by heat and drought; infrastructure will be threatened by extreme weather; fish stocks will be depleted; heat waves will claim lives; coasts will fall into the sea; and some aquifers will run dry.
But on a local level, which is what matters to people and governments, the impacts of climate change are devilishly difficult to model. They depend not only on changing weather but on how society responds. For instance, whether UK towns flood more in future depends not just on how high the seas get and how much it rains – which are difficult enough to model – but also on how rivers are managed, whether people build on floodplains and the area of land coated in concrete. Natural variability in the climate poses a further problem.
"Even if one had precise predictions of future meteorology, that would not mean one had precise predictions of droughts and floods," says Mike Hulme of King's College London. The same is true of food security, public health and access to water.
Communities won't get exact forecasts. "That would require a crystal ball," says Richard Betts of the UK Met Office in Exeter. "But we can assess risk, and whether risks are changing. Then it's up to society and politicians to decide what level of risk is acceptable." For example, New York City has decided the risks are great, so it has a plan to hold back rising seas.
To find out how people are experiencing climate change, Warner, van der Geest and their colleagues went to nine countries in Asia, Africa and Micronesia, surveyed 3269 households, and conducted 100 focus groups and interviews (see "Voices from the front lines").
"We find people who are already experiencing a lot of climatic variability, and people who are doing a lot themselves, not just changing what they do but also who have traditional systems already in place to spread risk," says van der Geest. "If a farmer in Africa has two hectares, he will try to diversify his crops and sowing dates so that if there's a drought he doesn't lose everything in one go."
Events caused by sea level rise are some of the few that can be firmly linked to climate change. To cope with saltwater invading fields, more Bangladeshi farmers are planting salt-tolerant rice. Nearly a third of those surveyed have flushed their fields with fresh water, either bought from neighbours or drained from rivers using new irrigation channels.
Coping mechanisms
In Bhutan, farmers say the monsoon is changing, so they must cope with more variable rains. The majority of those surveyed said they perform rituals, but half changed their systems of sharing water with their neighbours, or bought water. Some relatively wealthy farmers have bought gasoline pumps to bring water up from lowland rivers.
Many farmers have had to relocate, some repeatedly. After a severe flood struck Mozambique in 2001, the government moved people to higher ground. But these locations are vulnerable to drought and have poorer soils. Many kept their houses on high land but moved their fields back down, and now have to spend time commuting back and forth. Yields have improved, but the farmers run the risk of losing entire harvests to floods.
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