Climate Change: Keeping Sight of the Bigger Picture

Article excerpt

The U.N.'s Intergovernmental Panel on Climate Change (IPCC) will present a summary of its Fifth Assessment Report today, setting out the latest scientific evidence on climate change. The Met Office, the UK's weather bureau, is a world leader in climate science and a key contributor to the report.

We are living in a changing world. 2012 was among the ten warmest years on record - continuing the long-term trends we have seen in our changing and varying climate. As carbon dioxide levels continue to climb, these changes are not just confined to global temperatures. The bigger picture shows evidence of a changing world in rising sea levels, melting Arctic sea ice, and shrinking ice sheets.

This evidence is indisputable. Observations across the climate system, from land-based stations and ocean buoys to international satellites, show a warming planet. The fundamental physics is clear; carbon dioxide traps radiation and warms the planet. If we increase carbon dioxide levels in the atmosphere, temperatures will rise and a warmer world will be a more challenging place for us to live.

In 2012, and again this year, many parts of the world have been affected by damaging and costly extreme events; from major heatwaves, droughts and wildfires to extreme cold, excessive rainfall and flooding. Thousands of lives have been lost, over 100 million people have been affected and the damage runs to tens of billions of U.S. dollars.

In Taiwan, typhoons Soulik, Trami, and Usagi have caused significant damage this year. Typhoons are not new, but climate scientists predict that these and other extreme weather events will occur with increasing frequency and strength as the climate changes. There is some evidence to show this is happening already: The National Science Council's "Science Report of Taiwan Climate Change 2011" indicates that the average number of typhoons affecting Taiwan each year has risen from just over four in 1960 to almost six now. In fact, on average there were six and a half typhoons per year from 2000 to 2009. The report also points out that severe torrential rain used to affect Taiwan once every three to four years before 2000 but now happens once a year on average.

A new paper by scientists from the UK and the U.S. provides evidence that human influences on the climate played a role in the severity of a number of these global events. For example, the paper concludes that the frequency of occurrence of the extreme heat experienced in the U. …