(CNN) -- A map of significant climate events for the United States in June looks almost apocalyptic: hellish heat, ferocious fires and severe storms leaving people injured, homeless and even dead.
That followed a warm
winter and early season droughts. News came Monday that the mainland
United States experienced its warmest 12 months since the dawn of
record-keeping in 1895.
And on Tuesday, the
National Oceanic and Atmospheric Administration (NOAA) released a report
calling 2011 a year of extreme weather.
Remember Hurricane Irene?
Or the floods in Thailand and southern China and the deadly drought in
the Horn of Africa? Heavy rains in Brazil caused massive landslides and
much of Europe suffered through a sweltering heatwave.
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It's tempting to simplify things and blame it all on global warming.
After all, nine of the top 10 warmest years globally have occurred since 2000, according to NOAA.
But weather can be complicated.
The real challenge is
figuring out whether a particular storm or flood was due to climate
change or natural variables, said Chris Field, founding director of the
Carnegie Institution's Department of Global Ecology.
The NOAA report, for
instance, noted some events that were exacerbated by other factors.
However, climate change increases global risks, Field said.
"As we change the climate, we're shifting the odds for extreme weather," he said.
It's sort of like upping your chances of a car accident if you're speeding.
The four classes of
extremes -- high heat, heavy precipitation and floods, duration and
intensity of droughts and extremes related to higher sea levels -- have
changed in the last 50 years, Field said.
"Increasingly, we are loading the dice towards these very damaging kinds of extremes," he said.
But that's not to say every weather event is related to warming temperatures.
Southern Greenland,
northern Russia, and the eastern two-thirds of North America have felt
the greatest warmth in 2012, but many places -- Alaska, Mongolia and
most of Australia -- have been cool anomalies.
The men's final at the Wimbledon
tennis tournament Sunday was stopped briefly for rain. Rain, in
Britain? Although it has a reputation for sogginess, it's been cooler
and wetter than normal for the last few months in the British isles.
America's northwest has also escaped the heat. The state of Washington just marked its seventh coolest June ever.
"When you've got a
planet that's nearest warmest levels on record, that doesn't mean every
part of the world is going to be the warmest ever," said Jeff Masters,
director of meteorology for Weather Underground.
"The U.S. has been unlucky enough to be in that sort of pattern," he said.
Jake Crouch, a climate
scientist at the National Climatic Data Center, said weather patterns --
including the jet stream or the ocean-atmosphere systems in the Pacific
known as El Niño and La Niña -- have a great effect on weather.
In 2011, two
back-to-back La Niñas, each characterized by cooler-than-average water
temperatures in the eastern Pacific, affected significant weather events
-- including droughts in the southern United States and northern Mexico
and in east Africa.
There is debate over how
climate change affects such weather patterns but the NOAA-led "state of
the climate" report said La Niña-related heat waves are now 20 times
more likely to occur than 50 years ago.
Scientists also analyzed
the United Kingdom's very warm November 2011 and a very cold December
2010. They said that cold Decembers are now half as likely to occur
versus 50 years ago, whereas warm Novembers are now 62 times more
likely.
The report pointed out that some weather events, like the Thailand flooding, are influenced by humans in other ways.
"Although the flooding
was unprecedented, the amount of rain that fell in the river 'catchment'
area was not very unusual," the report said. "Other factors, such as
changes in reservoir policies and increased construction on the flood
plain, were found most relevant in setting the scale of the disaster."
The 2012 hurricane
season has gotten off to a robust start, though meteorologist Thomas
Downs of Expert Weather Investigations attributed that to a cyclical
warming of Atlantic waters.
"We've had a tremendous start to the system. We are in the middle of a warm phase," he said.
Hurricane Andrew in 1992 was devastating, but it was also the first named storm of that year -- in August.
By contrast, this year,
the United States has already lived through four named storms -- two in
May and two in June. The last was Tropical Storm Debby, which flooded Florida.
The warmer waters can lead to warmer temperatures on land, Downs said. So can extended drought.
"The biggest thing of
this year is the cumulative effect of the last two seasons. Some parts
of the United States have been under drought conditions for the past two
years," he said, and did not have much rain in April and May. Less
solar energy is absorbed by hot, parched land.
"The drought amplifies temperatures -- 90 becomes 100. 100 becomes 105."
"The reality is when you
do have extreme weather, it is highlighted," Downs said. "People want
to attribute it to one factor or another."
The other reality is
that Americans and others will likely be paying a lot more for cereal,
sweeteners and meat as the price of corn goes up because of failed
crops.
"The crops are hurting," said Chad Hart, a grain market specialist at Iowa State University.
The eastern part of the
Corn Belt is especially hard-hit. In states like Iowa, farmers are in
the critical stage of corn pollination.
"We need a good inch of moisture this week," Hart said. "And there's no rain in the forecast.
"That means we are looking for a much lower yield for crops we produce in the Midwest."
That means farmers will
be devastated and consumers could see higher prices at the grocery store
for corn, soy and wheat products, as well as meat from animals raised
on corn feed.
They will also be paying more to utility companies for running air-conditioners as the sizzling summer continues.
"In July, August and September, there's an above-average chance of warmer-than-average temperatures," Crouch said.
The hottest year on record for the United States is 1998. Crouch said 2012 is on track to beat it.
Perhaps people should get used to hotter temperatures, experts say, because the trends point that way.
A heatwave that occurred every 20 years will, by the year 2080, occur every one to two years, Field said.
The extreme weather the
world is seeing now is a precursor to more, he said. And it paints a
picture of what global warming looks like.
"There are a lot of
steps that can be taken to prepare people for climate extremes," he
said. "It's kind of a situation that warrants very serious thought."
In releasing the state
of the climate report Tuesday, Deputy NOAA Administrator Kathryn
Sullivan said 2011 will be remembered for extreme weather. This year
seems to be on the same track.
From now on, she said, every weather event takes place in the context of a changing global environment.
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