It's hot out there. But this time, it's more than idle watercooler talk, according to weather scientists.
At the same time the
National Oceanic and Atmospheric Administration's National Climatic Data
Center has released a report noting that this spring in the United
States has been the warmest since record-keeping began in 1895, a group
of scientists has published a paper in the journal Nature warning that
the planet is approaching a critical tipping point because of climate
and other factors.
Rampant population growth
and changes to the environment caused by humans, including the burning
of fossil fuels and the conversion of nearly 43% of the planet's land to
farms or cities, threaten to cause an abrupt and unpredictable shift in
the global ecosystem, 22 scientists from five countries said in their
paper.
In its report issued
Thursday, the climate data center said the average U.S. temperature
between March and May was 57.1 degrees, 5.2 degrees above the long-term
average from 1901 to 2000.
While May was only the
second-warmest on record, it was still in the top third for monthly
average temperatures, marking 12 consecutive months with temperatures in
that range, said Jake Crouch, a NOAA climate scientist.
"For that to happen 12 times in a row in a random circumstance is one in 540,000," he said.
Globally, NOAA reported
in May that the average temperature in April was 1.17 degrees warmer
than the average from the past century, making it the fifth-warmest
April since at least 1880.
It was the 326th consecutive month that global temperatures exceeded the 20th-century average, NOAA said.
The warm spring weather
in the United States was partially the result of the waning La Niña, a
pattern of below-average sea surface temperatures in the central Pacific
that tends to help direct the high-level jet stream and influence
weather patterns nationwide.
But it was also partially the result of long-term climate change, Crouch said.
"The pattern we've been in for the last 12 months is exactly what we would expect in climate change," he said.
The notion of long-term
climate change -- particularly as caused by humans -- is politically
controversial but generally accepted as fact by most scientists.
The Nature article, also
published Thursday, said that such shifts in weather patterns and
human-induced changes could have sudden and unpredictable effects on the
global ecosystem, including the collapse of food supplies and other
problems.
It warned that "widespread social unrest, economic instability and loss of human life could result."
The paper calls for
improvements in efforts to detect critical changes in the ecosystem, as
well as reduced global population growth and energy use and other
measures.
A shift in the biosphere
is possible by 2100 if nothing is done to better predict changes and
act upon them, said Anthony D. Barnosky, professor of integrative
biology at the University of California, Berkeley and lead author on the
Nature article.
"If we do nothing, I
personally think we hit this tipping point," Barnosky said Friday. "It
means the world will be very different, losing biodiversity and
(affecting where) species live in particular places."
The scientists are
concerned that the biosphere has seen dramatic changes since the last
Ice Age, factoring in the climate and a huge increase in global
population. The current population of 7 billion is expected to increase
to 9 billion within three decades.
"People have become a
geological force in their own right, and we are changing the planet in
ways every bit as dramatic as major geological events," Barnosky said.
"We are becoming much more dominant organisms in Earth by our sheer
numbers and the way we use natural resources."
Barnosky said the NOAA
report buttresses his group's findings on global temperatures. The mean
temperature by 2070, perhaps earlier, will be higher than it has been
since the human species evolved, according to the Nature article.
When it comes to policy,
Barnosky suggests that countries look at new and clean energy
technologies as the world's petroleum supply draws down. Also crucial
are food production and distribution, with an eye toward not letting the
percentage of land disturbance worldwide -- currently 43% -- surpass
50%. The loss of rain forests, he said, is a reminder of the loss of
biodiversity as humans try to meet their needs.
Nations are at a
crossroads "where if we recognize these major ways we are changing the
planet and actively guide how we are making those changes, we can move
our biosphere in directions we want it to," Barnosky said.
"I see people are clever
and resourceful when they realized there is a major global problem," he
said. "My fear is that we keep our heads in the sand and we don't
recognize these things going around us until it is too late."
Written by Michael Pearson and Phil Gast@CNN
No comments:
Post a Comment