Some 13 million people in Djibouti, Eritrea, Ethiopia, Kenya and Somalia have been experiencing one of the worst humanitarian crises in decades. The region’s most severe drought in 60 years has caused widespread starvation and made access to clean water and sanitation extremely difficult . These conditions not only directly affect local communities today, but also weaken their resiliency to cope with future droughts, diminishing prospects for water and food security in the years to come. Temperatures in the region are expected to continue rising while rainfall patterns change. The crisis in the Horn of Africa is only one of the events in 2011 that exemplify the challenges to be met in the face of an increasingly variable and changing climate worldwide.

2011 was a year of record-breaking weather events, which caused a large number of deaths and billions of dollars in damage. It was also the tenth warmer year and the warmest La Nina year on record, as well as the year in which the second lowest seasonal minimum extent of Arctic sea ice was recorded. Scientists have established a new international partnership to assess, on a case-by-case basis, the likelihood that exceptional weather events are caused or exacerbated by the global temperature increases observed during the past century. In addition, by investigating rainfall variability, scientists have already found evidence that anthropogenic greenhouse gas emissions substantially increase the risk of extreme events occurring.

An extreme weather event is defined as one that is rare within its statistical reference distribution at a particular location. While natural variability makes it very difficult to attribute individual extreme weather events to climate change, statistical analyses show that the overall trends of many extreme events are changing. A new report of the Intergovernmental Panel on Climate Change (IPCC) concludes that climate change is leading to changes in the frequency, intensity, length, timing and spatial coverage of extreme events. According to this report, it is virtually certain (99-100 per cent probability) that the frequency and magnitude of daily high temperatures will increase during the 21st century while those of cold extremes will decrease. The IPCC report expresses great confidence that there will be increases in events related to heavy precipitation and coastal high water, the latter due to rising sea levels. But despite a number of devastating floods in 2011, such as those in Australia, Pakistan and Thailand, evidence concerning regional long-term changes in flood magnitude and frequency is not as prevalent, partly because of a lack of available observational data at the appropriate time and spatial scales.

The United States National Oceanic and Atmospheric Administration (NOAA) reported that in the first six months, 2011 had broken the record for the costliest year in terms of weather disasters in the United States. By the end of 2011, the United States experienced 14 “billion-dollar disasters” – Economic losses due to disasters are higher overall in developed countries than in developing ones. As a proportion of GDP, however, losses are much higher in developing countries. Over 95 per cent of extreme event fatalities in the past several decades have occurred in developing countries. Developed countries often have better financial and institutional mechanisms to cope with extreme events and their impacts. Future exposure and vulnerability to such events can be mitigated by integrating disaster risk reduction planning with economic development and climate change adaptation planning. Early warning and disaster risk reduction plans and strategies are essential, while documentation of individual events adds to the pool of knowledge and lessons learned. Many regions are already carrying out disaster risk reduction and preparedness activities, including public awareness initiatives and improvements to early warning systems and infrastructure.

Source : UNEP Year Book 2012