Global warming is increasing the frequency and ferocity of some extreme-weather events, highlighting the need for governments at all levels to reduce vulnerabilities and increase the resilience of their citizens to such events. That's according to a new report from the United Nations-backed Intergovernmental Panel on Climate Change (IPCC). The spectrum of tools available to help is familiar: improved forecasts and warnings for severe weather, rigorously enforced zoning and building codes, and restoration of ecosystems that serve as buffers between people and river floods or coastal-storm surges, for instance. The success of such efforts, particularly in developing countries, depends in part on reducing poverty and social inequalities that can deprive people of the help they need to prepare for and cope with severe weather, the report's authors say.
In any event, the climate has "profound changes on the way," says Chris Field, director of the Carnegie Institution for Science's Department of Global Ecology at Stanford University in California. In managing the risks from disasters, current and future, "one of the key messages from the report is that opportunities need to be taken advantage of at every scale – the local scale, the national scale, and the international scale," said Dr. Field, who cochairs one of two of IPCC working groups that contributed to the report. A briefing about the report was held Friday in Kampala, Uganda, where the two working groups were holding a joint meeting. The challenge in looking for trends in weather extremes is that the extremes still tend to be relatively rare, researchers say. Still, over the past decade, the researchers say, additional events and improvements in the tools to analyze them have allowed researchers to identify patterns in some climate features with increasing confidence. Already, global warming's fingerprints are evident in broad temperature and precipitation trends over the past 60 years, say scientists from the two working groups – one that focuses on climate science and one that focuses on assessing the effects and vulnerability.
Globally, the number of warm days and nights has grown, while the number of cold days and nights has decreased. In the United States, researchers have documented an increase in the number of high-temperature records set per decade and a decrease in the number of records lows set. Also globally, the number of storms delivering a deluge rather than gentle showers has increased in more regions than those regions recording decreases in intense rain or snowfall – a sign that the warming atmosphere is holding more moisture. Moreover, a warming climate has contributed to sea-level rise, the report says. This has led to an increase in incidents of extreme coastal flooding during storms.