Worse Floods Ahead As Climate Warms

Jul 24th, 2013 | By | Category: Development and Climate Change, Disaster and Emergency, Disasters and Climate Change, Ecosystem Functions, Global Warming, International Agencies, Resilience, Vulnerability

rescue-2CNN: “Atmospheric rivers”, airborne corridors of concentrated moisture which carry huge volumes of water, are set to get wider and longer, causing more frequent and catastrophic floods as the atmosphere warms.

Heavy and prolonged rainfall will cause both more frequent and more severe flooding across the United Kingdom and the rest of north-west Europe as the atmosphere continues to warm, say British and American scientists.

A study in IOP Publishing’s Environmental Research Letters of what are known as atmospheric rivers pins the blame for the increasing flood risk firmly on man-made climate change and says the same problem will afflict other parts of the planet.

Researchers at the University of Reading near London, and the US University of Iowa, describe how atmospheric rivers carry vast amounts of water vapour around the Earth, delivering heavy and prolonged rainfall, particularly to mountainous areas. They were responsible for the protracted winter and summer floods in the UK in 2012, which caused an estimated $1.6 billion (£1 bn) in damage.

In a warming world the atmosphere can carry more water and the research showed that the rivers, typically running a kilometer above the earth, 300 kilometres wide and thousands of kilometres long, would become larger and capable of delivering even bigger quantities of prolonged rainfall.
Longer danger period

An example of their potential danger is the atmospheric river that caused the severe flooding on 19 November 2009 over north-west Britain. As it approached the coast it was transporting a moisture volume 4,500 times the average gauged flow of the river Thames through London.

In California, where atmospheric rivers (ARs) have already been assessed, the climate models predict that the number of years with these features will increase. To discover what could happen in Europe the models were tested against the known flooding events between 1980 and 2005, and the researchers found that they could accurately simulate what actually happened.

This gave them confidence to test what would happen in the future. All the models showed that with more greenhouse gases emitted by humans there would be a doubling of the number of atmospheric rivers later this century compared with the 1980 to 2005 period. Most of these events occur in the winter, but in a warmer world the danger period is extended.
Effects will be widespread

Because of the way the warmer atmosphere is able to carry more water and deliver much higher rainfall totals, the potential for far worse floods from each of these rainfall events is much increased.

The head of the research, Dr David Lavers, from the department of meteorology at the University of Reading, said: “ARs could become stronger in terms of their moisture transport. In a warming world, atmospheric water vapour content is expected to rise due to an increase in saturation water vapour pressure with air temperature. This is likely to result in increased water vapour transport.

“The link between ARs and flooding is already well established, so an increase in AR frequency is likely to lead to an increased number of heavy winter rainfall events and floods. More intense ARs are likely to lead to higher rainfall totals, and thus larger flood events.”

The paper points out that while the scientists were specifically looking at the atmospheric rivers that caused heavy rainfall in Europe, these storms affect many temperate regions of the planet. As the atmosphere warms, it is likely that they will increase the risk of flooding elsewhere.

Source: Climate News Network

About

Started in year 2010, ‘Climate Himalaya’ initiative has been working on Mountains and Climate linked issues in the Himalayan region of South Asia. In the last five years this knowledge sharing portal has become one of the important references for the governments, research institutions, civil society groups and international agencies, those have work and interest in the Himalayas. The Climate Himalaya team innovates on knowledge sharing, capacity building and climatic adaptation aspects in its focus countries like Bhutan, India, Nepal and Pakistan. Climate Himalaya’s thematic areas of work are mountain ecosystem, water, forest and livelihood. Read>>

Himalayan Nations at Climate Change Conference-CoP21

Over 150 heads of state and government gathered in Paris at the UN climate change conference on Monday, 30 November, the largest group of leaders ever to attend a UN event in a single day. In speech after speech, they provided political leadership and support to reach an ambitious and effective climate change agreement by…

Read more…

Comments are closed.

seo packagespress release submissionsocial bookmarking services