Tiempo Climate Newswatch

In a week when flooding affected millions of people around the world, the United Nations deputy humanitarian coordinator Margareta Wahlstrom warned that the economic toll of flooding on a community's housing, health and infrastructure remains devastating, despite improvements in early warning systems. "The great risk is that large numbers of people are living in the most vulnerable areas in the world," she said. The inundation of homes and farmland affects some 500 million people a year.

The current flooding in the Indian state of Bihar is said to be the worst in living memory, with around ten million people affected. Over 500 people have died through drowning, disease and snakebites. More than 50,000 people are suffering from diarrhoea in Bangladesh. John Holmes, the United Nation's under secretary general for humanitarian affairs, said that nations should examine ways to protect vulnerable populations. "It's the worst we've seen for 50, 60, 70 years and we're beginning to see a pattern of flooding around the world," he warned. "There is an enormous problem because climate change is a reality already... We need to anticipate it and not just respond to it." "If you invest in disaster risk reduction, and what that means is not building on flood plains, having shelters for people to go to, recognizing the problems before they happen and anticipating them, that investment is one of the best investments you can make, he continued."

Scientists predict that the planet's temperature will plateau for two years before increasing rapidly to the year 2014. During at least half the years after 2009, global temperatures will exceed the current record, which was set in 1998. The current break in the warming trend is the result of natural cooling in the Southern Ocean and tropical Pacific.

The forecast is the result of a new modelling experiment by Doug Smith and colleagues at the Hadley Centre, located in Exeter in the United Kingdom. The experiment takes account of short-term causes of climate variability as well as longer-term factors such as global warming. "Occurrences of El Niño, for example, have a significant effect on shorter-term predictions," said Smith. "By including such internal variability," he said, "we have shown a substantial improvement in predictions of surface temperature."

Climate change could be reducing the growth rate of trees in tropical rainforest by as much as a half, according to a recent study. The analysis was based on data extending back to 1981 from hundreds and thousands of trees in Panama and Malaysia. "If we're correct and the temperature is driving these changes, this is something we're going to see in a lot more places," said the study's lead author Ken Feeley of Harvard University's Arnold Arboretum in Boston in the United States.

Feeley acknowledges that, under increasing carbon dioxide alone, the growth rate will increase, but, he says, "there are lots of factors - it's naïve to think of any one in isolation." He reckons the effect may occur because photosynthesis is impaired if the temperature rises over a certain point. The finding has "very important implications," he warns. "We may need to look elsewhere for our excess carbon sink."