http://www.guardian.co.uk/environmen...weather.uknews


Global warming: Met Office predicts plateau then record temperatures

* Ian Sample, science correspondent
* The Guardian
* Friday August 10 2007



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.