November 18, 2011 / 4:04 PM / 8 years ago

UPDATE 1-Extreme weather to worsen with climate change-IPCC

* More heat waves, heavier rains, worse cyclones likely
    * Nations meet in South Africa on climate change this month

 (Adds details, quotes, background, reaction)	
    By Elias Biryabarema	
    KAMPALA, Nov 18 (Reuters) - An increase in heat waves
is almost certain, while heavier rainfall, more floods, stronger
cyclones, landslides and more intense droughts are likely across
the globe this century as the Earth's climate warms, U.N.
scientists said on Friday.	
    The U.N. Intergovernmental Panel on Climate Change (IPCC)
urged countries to make disaster management plans to adapt to
the growing risk of extreme weather linked to human-induced
climate change, in a report released in Uganda.	
    The report gives differing probabilities for weather events
based on future greenhouse gas emissions scenarios, but the
thrust is that extreme weather is likely to increase and that
the likely cause is humans.	
    The IPCC defines "likely" as a 66-100 percent probability,
while "virtually certain" is 99-100 percent.	
    "It is virtually certain that increases in the frequency and
magnitude of warm daily temperature extremes ... will occur in
the 21st century on the global scale," the IPCC report said.	
    "It is very likely that the length, frequency and/or
intensity of ... heat waves will increase," it added. 	
    "A 1-in-20 year hottest day is likely to become a 1-in-2
year event by the end of the 21st century in most regions,"
under one emissions scenario.	
    An exception is in very high latitudes, it said. Heat waves
would likely get hotter by 1-3 degrees Celsius by mid-21st
century and by 2-5C by late-21st century, depending on region
and emissions scenario, it said.	
    Delegates from nearly 200 countries will meet in South
Africa from Nov. 28 for climate talks with the most likely
outcome modest steps towards a broader deal to cut greenhouse
gas emissions to fight climate change.	
    The IPCC report found human emissions have "likely" caused
more extreme heat waves and sea surges, but is less sure about
the link between man-made climate change and worse floods.	
   "There is evidence that some extremes have changed as a
result of anthropogenic influences, including increases in
atmospheric concentrations of greenhouse gases," it said. 	
    The risks posed by increasingly erratic weather have been
highlighted by a spate of disasters in recent years, such as
flooding in Thailand and Australia, droughts in east Africa and
Russia and hurricanes in the Caribbean.	
    The United Nations, the International Energy Agency and
others say global pledges to curb emissions of CO2 and other
greenhouse gases are not enough to prevent the planet heating up
beyond 2 degrees Celsius, a threshold scientists say risks an
unstable climate in which weather extremes are common.	
    Global carbon emissions rose by a record amount last year,
rebounding on the heels of recession.	
    The report did not address this, but recommended that action
is taken now to shore up the defences of vulnerable states,
including early warning systems, better land use planning,
restoring ecosystems that act as buffers, enforcing building
codes and weather-proofing infrastructure.    	
    "The clear message from this report is that there are a lot
of smart things we can do now that reduce the risk of losses in
disasters," co-author Chris Fields told Reuters.	
    "It is likely the frequency of heavy precipitation ... will
increase in the 21st century over many areas," the report said,
especially in "high latitudes and tropical regions."	
    There was "medium confidence" this would lead to "increases
in local flooding in some regions", but this could not be
determined for river floods, whose causes are complicated.	
    Tropical cyclones were likely to become less frequent or
stay stable, but those that do form are likely to get nastier.	
    That, coupled with rising sea levels were a concern for
small island states, the report said.	
    Droughts, perhaps the biggest worry for a world with a
surging population to feed, were also expected to worsen.	
    The global population reached 7 billion last month and is
expected to reach 9 billion by 2050, according to U.N. figures.	
    "There is medium confidence that droughts will intensify in
the 21st century ... due to reduced precipitation and/or
increased evapotranspiration," in "the Mediterranean ... central
Europe, central North America, Central America and Mexico,
northeast Brazil and southern Africa."	
    There was a high chance that landslides would be triggered
by shrinking glaciers and permafrost linked to climate change.	
    "Today's IPCC report brings home the inescapable fact: that
climate change is ... causing an escalation in impacts ... most
of which are increasingly being borne by the developing world,"
Greenpeace climate policy coordinator Maria Ryding said.	
    Sceptics have questioned the models the IPCC uses to make
its climate predictions, but Fields defended the science: "There
are many cases in which just from observations, we've seen a
change," he said.	
    "Climate models are only some of the tools used to make
future projections. Some ... are based on projecting historical
data forward or what we know about the physics of the system.
Lots of observations are built in for us to test how they work."	
 (Writing and additional reporting by Tim Cocks; Editing by
Janet Lawrence)
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