British scientists are predicting a succession of record-breaking high temperatures in the most detailed forecast of global warming's impact on weather around the world.
Powerful computer simulations used to create the world's first global warming forecast suggests temperature rises will stall in the next two years, before rising sharply at the end of the decade.
From 2010, they warn, every year has at least a 50% chance of exceeding the record year of 1998 when average global temperatures reached 14.54C.
The study's findings raise the prospect of hotter summers and episodes of torrential rain in the UK; 1998 brought temperatures peaking at 32.2C, although the UK record was set in 2003 at 38.1C.
The forecast from researchers at the Met Office's Hadley Centre in Exeter reveals that natural shifts in climate will cancel out warming produced by greenhouse gas emissions and other human activity until 2009, but from then on, temperatures will rise steadily. Temperatures are set to rise over the 10-year period by 0.3C. Beyond 2014, the odds of breaking the temperature record rise even further, the scientists added.
The forecast of a brief slump in global warming has already been seized upon by climate change sceptics as evidence that the world is not heating. Climate scientists say the new high-precision forecast predicts temperatures will stall because of natural climate effects that have seen the Southern Ocean and tropical Pacific cool over the past couple of years.
The forecast marks a shift in thinking by climate change researchers. Instead of using their models to look many decades ahead, they will focus on the very near future. The hope is that forecasts will be more useful to emergency planners in governments and companies by warning of droughts and other extreme conditions a year or two ahead. Previously, the models have been used to show that global temperatures may rise 6C above pre-industrial levels by 2100.
"If you look ahead on a 50- to 100 year time frame, then global warming is the big thing for the climate, but if you're working on a project that is only designed to last for the next few years, that information doesn't make much difference to you," said Doug Smith, a climate scientist at the Hadley Centre.
A team led by Dr Smith set computers working on the forecast after plugging in temperature measurements taken from the world's oceans and atmosphere. The team then checked the accuracy of the forecasts by getting it to predict climate change throughout the 1980s and 1990s.
So far, only forecasts of temperature changes have been released in the journal Science, but the models also calculate changes in rainfall, drought risk and other effects of climate change that directly impact flood defences and other vital responses to global warming.
"The people who can use long-term climate information are few and far between. It's fine if you're building a skyscraper or something else that's going to be in place for 100 years, but for most people, it doesn't matter much. It's much more critical to know what is going to happen in the next year or two and that is something climate scientists have always struggled with," said Chris West, director of the UK climate impacts programme at Oxford University.
It is running an ongoing project assessing the costs of extreme weather events such as the torrential downpours that recently brought serious flooding to parts of Yorkshire and southern England.
A pilot study with Oxfordshire county council revealed that in the past 10 years, the authority had spent more than £10m dealing with the consequences of extreme weather. "If a climate model can tell you when your infrastructure is going to fail so many years into the future, it can inform your decision making," Dr West said.
The latest forecast shows how temperatures will change year on year over the coming decade. According to Dr West, it is the sort of information that will be of enormous benefit for planners and emergency responders across government, local councils and companies. Details in the forecast are ultimately expected to feed into decisions over vital infrastructure, such as road surfacing, drainage, water storage and retail stocking.
Professor Phil Jones, director of the climatic research unit at the University of East Anglia, said the move towards near-term global warming forecasts was part of a concerted effort to combine weather forecasts with climate change predictions in a seamless way. The combined predictions would then allow people concerned about the potential impact of climate change to look ahead on any time frame to judge what actions they should take to prepare themselves.
The high-resolution forecast also reveals how global warming will happen in fits and starts, and that for the next year or two, temperatures are likely to remain stable before rising.
"A number of the sceptics are saying there's no warming because they look at the temperature record and see a peak in 1998 and cooler years after that. But we know the peak was because of an El Niño event and that comes out in this forecast," said Prof Jones.