Global Trends by Martin Khor

Monday 30 July 2012

Extreme weather events on the rise

It was lucky the Olympics opening ceremony was not washed out by rain, because heavy rain, floods, heatwaves and droughts are among extreme weather events on the rise this year.


Last Friday night’s opening ceremony of the Olympic Games in London was widely acclaimed for its spectacular display.  But besides the brilliant design and smooth implementation, another factor played an important role, and that is luck.

It was lucky that the ceremony was not ruined by rain.  Just a few weeks ago, much of Britain was deluged by floods caused by a lengthy spell of rain.  TV screens and newspapers were filled with images of cars washed down streets that had turned into rivers.

Many tennis matches at Wimbledon were interrupted by rain, and had to continue under a roof mechanically placed over the grass courts.

Even now, the Olympic Games organisers, athletes and spectators alike must be keeping their fingers crossed that there is no major downpour in the days ahead that will disrupt the competition.

The unusually intense rainfall and floods have reached historically the worst levels in the UK.  In January, a government report said that flooding caused by heavier rainfall will be Britain’s worst effect from climate change in coming decades, costing damage valued at many billions of pounds a year.

Extreme weather events are of course not confined to the UK but are taking place all over the world at an increasing rate, and with damaging intensity.

Only last week, at least 77 people died and thousands were displaced in the worst flooding to hit Beijing in more than 60 years.  This was due to a long and heavy downpour on 21 July. 

It was the heaviest rain in Beijing since records began in 1951, causing rivers to burst their banks and flood major highways, submerging cars with people trapped inside, and sweeping houses and people away.

Meanwhile, the United States is facing a severe heat-wave and drought.  This has caused significant falls in farm output, with serious effects on global food supply and prices.

The dry weather in the US is partly explained by caused by La Nina, which has a cooling effect on the Pacific Ocean, bringing warmer and dryer weather to the South of the US, including Texas whose agriculture has been devastated in the past year.

But many climate scientists are also linking the drought to climate change.  According to Peter Stott of the UK government’s Met Office Hadley Centre, La Nina is only part of the story.

Stott co-authored a recent study which links climate change with the Texas drought and other extreme weather events.  Interviewed by the Voice of America, he said his study found “clear evidence for human influence on the Texas heat wave and also in the very unusual temperatures we had in the United Kingdom in 2011.”

According to the study, the 2011 Texas drought was 20 times more likely to occur than in the 1960s as a result of emissions causing climate change.  The heat wave last November in England was 62 times more likely to have occurred than 50 years ago.

Scientists are cautious to note that it is difficult to pinpoint particular extreme weather events as being caused by climate change but new studies have found that climate change has made these events more probable.

Says Stott:  “It is the combination of natural variations of climate that is important here. We saw that in La Nina in Texas, but, over and above that, there is this additional climate effect that can and has indeed in the last year led to a greater vulnerability to extreme weather.”

In November 2011, a path-breaking report by the U.N. Intergovernmental Panel on Climate Change involving 100 scientists linked the increase in extreme weather events such as heavier rainfall and flooding, and heat-waves to climate change.

The report evaluates that there is at least a 66% chance that climate extremes have changed as a result of greenhouse gas emissions, and also notes that “economic losses from weather- and climate-related disasters are increasing”. 

The global insurance industry has reported that 2011 was a record year for catastrophes (many of them weather related), with economic losses of US$350-400 billion.

A report on extreme weather events and insurance by the Geneva Association shows that the number of natural catastrophes increasing from almost 400 in 1980 to 800-1,000 in the period 2006-2011.  The associated economic losses rose from about US$70 billion in 1980 to US$380 billion in 2011.

Notable extreme weather-related events in Asia in recent years include Thailand’s worst flooding in 50 years in September-October 2011 which had devastating effect on manufacturing, agriculture and homes, with losses estimated by the World Bank at US$45.7 billion. 

Pakistan suffered heavy rain and extensive floods in July-August 2010, which affected 20 million people, killed 2,000 and severely damaged agricultural production; in 2011 the country suffered another major flood which killed thousands more people.

Last year a severe drought hit Eastern Africa, threatening an estimated 12 million people with food shortage.   Again, scientists were careful not to link the shortage of rain to climate change, but were of the view that the changing climate increased the risk of such events.

There are many lessons from all these recent developments, including that policy makers must pay greater attention to the changing weather in their countries, that extreme weather events are not isolated and one-off events but part of a pattern.  

Priority should be given to putting prevention measures such as flood control in place before the disasters happen, and flood management in anticipation of their happening. 

And the growing evidence of the links between these extreme events with climate change should also prompt governments and social movements to increase their seriousness to tackle the causes of climate change.