Turn Down the Heat: Why a four degree Celsius warmer world must be avoided
World Bank Report November 2012 written by the PIK Potsdam
The report is based on new analyses of likely impacts and risks that would be associated with a 4° Celsius warming within this century. It outlines a range of risks, focusing on developing countries and especially the poor. A 4°C world would be one of unprecedented heat waves, severe drought, and major floods in many regions, with serious impacts on ecosystems and associated services. But with action, a 4°C world can be avoided and it may still be possible to hold warming below 2°C.
No nation will be immune to the impacts of climate change. However, the distribution of impacts is likely to be inherently unequal and tilted against many of the world’s poorest regions, which have the least economic, institutional, scientific, and technical capacity to cope and adapt. For example:
• Eventhough absolute warming will be largest in high latitudes, the warming that will occur in the tropics is larger when compared to the historical range of temperature and extremes to which human and natural ecosystems have adapted and coped. The projected emergence of unprecedented high-temperature extremes in the tropics will consequently lead to significantly larger impacts on agriculture and ecosystems.
•Sea-level rise is likely to be 15 to 20 percent larger in the tropics than the global mean.
• Increases in tropical cyclone intensity are likely to be felt disproportionately in low-latitude regions.
• Increasing aridity and drought are likely to increase substantially in many developing country regions located in tropical and subtropical areas.