'No time for resignation'

"For a long time the focus was all on mitigation. Now, interest is swinging to adaptation," says Cynthia Rosenzweig, who heads the Climate Impacts section at NASA's Goddard Institute for Space Studies. "Adaptation happens on the local scale, and that's where the changes are already happening," she added.

Climate change affects almost every area of our daily lives, according to Rachel Cleetus, a climate economist with the US-based advocacy group Union of Concerned Scientists. "It has impacts on our health, food security, possible conflict and migration: We can see coastal risk in some areas from sea level rise; there are droughts and wildfires," she told DW.

Decision-makers have to cope with considerable uncertainty when it comes to estimating the extent of climate impact risks, according to Hans Joachim Schellnhuber, director of PIK and climate advisor to the German government. "In some cases, there may only be a low probability that particular climate impacts will occur, but they might well cause an unacceptable amount of damage, so it would be better to avoid them."

Risky business

Climate impact researchers aim to help politicians manage the risks. Their work is based both on monitoring actual changes and developing computer models to work out the likelihood of particular impacts. The wide range of possible effects make systematic research very complex, says Wolfgang Lucht, head of Earth System Analysis at PIK and an expert in sustainability science at Berlin's Humboldt University.

There is also a huge range of possible feedback effects, where one impact in turn influences other factors and different sectors. Ocean acidification, for example, which happens when increasing amounts of CO2 are absorbed into the sea, can have an effect on the ecosystem but ultimately also on the food chain.

Agriculture is a key sector affected in many different ways by a changing climate. Cynthia Rosenzweig is in charge of AgMIP, an international project aimed at providing better climate forecasts for farmers. It links computer simulations on climate, crop yield and economic development. Ultimately, the network of experts from different areas of science and agriculture has the aim of improving food security for the planet's growing population.

AgMIP combines the computer models with monitoring at global, regional and local levels, and projects on the ground. In southern Africa, for instance, an interdisciplinary team is looking at different farming areas and their uses. They want to find out how the harvest will be affected by higher temperatures and whether this could be compensated for by changing crops, introducing new irrigation techniques or changing planting times.

Tipping points in climate consciousness?

The increase in extreme weather events over the last two decades has focused attention on the urgent need for adaptation, says climate economist Cleetus.

"In the US, this shows that climate change is not a future thing," she adds. "It is here and we are already feeling its impacts."

She says climate change has played a role in many catastrophes, including droughts, heat waves and Hurricane Sandy.

NASA's Rosenzweig, who is co-chair of New York City's Climate Committee, is convinced last year's devastating hurricane marked a tipping point in US awareness of climate change. She found interest in her work increased considerably following the devastation wreaked by Sandy.

Cleetus stresses the need for integrated future planning to prepare for future climate change impacts.

Adaptation has become a necessity to avoid or minimize damage from climate-related events.

But, says Wolfgang Lucht, this also highlights the need for measures to mitigate climate change by reducing emissions. Our capacity to adapt is not unlimited, he points out.

"We have evidence that climate change could have played a role in the collapse of complex civilizations," Lucht says. "It is not certain, but there are signs that changes in the environment could have had a major impact, for instance through changing the availability of resources a society relied on."

Lucht sees the shift to renewable energies as an attempt to effect a "controlled transition" before we are forced to change by other factors. He hopes assessments that illustrate the high cost of climate impacts will help speed up progress in international efforts to halt global warming.

The impacts of climate change will depend on the extent to which the temperature actually rises.

A recent climate report by the International Energy Agency documents a 1.4 percent rise in greenhouse gas emissions from the energy sector over the last year, resulting in a record high. If we continue on this course, the aim of keeping the rise in global temperature to two degrees Celsius will be impossible, according to the report. A rise of between 3.6 und 5.3 degrees would be more likely - with potentially disastrous consequences.

Lucht says resignation is not an option: "The worse the situation looks, the more effort we have to put into innovation and finding ways of reaching the goal."

The sustainability expert sees the transition to renewable energy currently underway in Germany as proof that there is an alternative path.

But every year of inaction on emissions is a wasted opportunity, he says. CO2 stays in the atmosphere for many years and will have an impact in the future.

"Our children may well reproach us one day for taking such a relaxed approach to such a key issue," Lucht warns.