Extremes
of Climate - Droughts
Global
warming results in more
frequent and more severe droughts
There are strong
implications from scientific climate models
that global warming
due to increased greenhouse gas emissions has been associated with the more frequent occurrence of extreme
climatic events, and that humankind is the
cause of global warming.
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As the Earth
warms, land and sea surface temperatures increase
enabling it to retain more water moisture in the
atmosphere resulting in initial decrease in
precipitation. The combination of a decrease in
rainfall and increased evaporation will lead to
more severe and longer-lasting droughts in some
areas. It also mean rampant flooding, when
precipitation finally occurs.
Thus, while one part of the
world is experiencing searing drought, the other part of the
world will be experiencing serious flooding, as is happening in
China, Australia and Africa in 2009. |
Warming is expected to pose serious challenges
to global
food security and stability.
Sub-Saharan Africa will be worst hit by impacts
of climate change. In the Sahelian region of
African, warmer and drier conditions have led to
shorter growing season, reduced crop harvests
and crop failure.
Longer dry seasons and more uncertain rainfall
are prompting urgent adaptation measures in
Africa.
Moscow Suffers
Hottest Day Ever
July
- August 2010 News
Russian President Dmitry
Medvedev attributed it to Climate Change
Concerns of
Food Security
Russia suffered the
worst drought and heat wave in more than a
century, with temperatures reaching a searing
record of 39oC. More than 500,000
hectares of land have burned, and an estimated
1/5 of the country's wheat crop failed due to
lack of rain. The month-long drought has caused
22000 fire
islands in central
Russia.
Pollution levels in parts of the city exceeded
10 times the normal safety limits. Death toll
rose to 50, with 3069 lost their homes and 1902
buildings destroyed.
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Birch
forests in C. Russia severely
damaged by drought
Pic: S
Karpukhin/Reuters |
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Hundreds of thousands
of firefighters, including army troops were
deployed to battled the raging forests fires. A
state of emergency has been declared in more
than 20 regions. Russia announced to ban all
grain exports for the rest of 2010 year, sending
wheat prices soaring to a two-year high and
raising the possibility of inflated food prices.
The unprecedented heat wave had caused billions
of dollars worth of damage and concerns of
food security.
Russian President Dmitry Medvedev, was quoted saying "Our country has not experienced such a heat wave in the last 50 or even 100 years. We need to learn our lessons from what has happened, and from the unprecedented heat wave that we have faced this summer.""Everyone is talking about climate change now. Unfortunately, what is happening now in our central regions is evidence of this global climate change, because we have never in our history faced such weather conditions in the past. This means that we need to change the way we work, change the methods that we used in the past."
Fires to Follow Floods as Wild Weather Hits
Australia: Feb 06 2009 AFP
Eastern Australia
braced for more fires and floods; as the south
faced extreme heat and heavy rain threatened to
swell floodwaters ravaging the north. A
once-in-a-century heatwave was forecast to
intensify over the weekend with high
temperatures and dry winds producing the worst
wildfire conditions in 25 years, authorities
said.
If you want to know what the U.S.
southwest faces in the coming
decades if we don’t reverse
greenhouse gas emissions trends
quickly, just look to Australia.
Temperatures were running at about
one degree “above any previous
comparable drought. That is
substantially hotter, and that one
degree is a global warming signal.”
Data collected shows widespread drying from
the 1970s to the early 2000s over much of Europe
and Asia, Canada, western and southern Africa,
and eastern Australia.
Severe droughts
too, occurred in southern England in 1976, as a
result of 18 months of below average rainfall
concurrent with temperatures of 4° C above
average. The heat-stress caused numerous daily
fire break outs. In Surrey alone, the fire
service answered 11,000 calls within a period of
five months. Just crop failure alone resulted in
an estimated loss of £500m.
The United States and
many coastal regions had on
the other hand, become wetter overall during the
last 50 years.
Extremes may also occur
at a particular place, but at different times.
For example the summer of 2002 in Europe brought
widespread floods but was followed a year later
in 2003 by record-breaking heat waves and
drought. Over recent years
within China (for example 2008), droughts occur
in the north while
floods occur frequently in
the south.
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Washbasins to
help
irrigate crops in China 2009 (AP
Photo) |
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China's worst drought in five
decades
hitting eight
wheat-growing provinces (2009) |
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Chinese
soldiers use washbasins to help irrigate crops
Chinese soldiers use
washbasins to help irrigate crops in a field at
Hejie village in Xuchang in China's Henan
province Friday, Feb. 6, 2009. The People's
Liberation Army deployed over 1,000 soldiers to
help irrigate crops in Xuchang.
China has declared the
highest-level emergency for the first time to
combat the country's worst drought in five
decades that has hit eight wheat-growing
northern provinces and left more than 4 million
people without proper drinking water.
AP - Hier,
Effects of these extremes will bring costly
consequences
Frequent droughts
will adversely
affect sea and land ecosystems, coastal systems,
freshwater security,
food security
and
land
degradation.
The impacts incurred on
environmental and ecological systems during the
1999 drought in the United States may provide a
clearer picture of the probable drought
effects. Shortage of fresh water increased the
salinity of river waters posing risks to river
habitats. It also created stress on fresh water
supplies for consumption and agriculture. As
future sea level rise shifts the
saltwater-freshwater boundary farther inland,
droughts will exacerbate the geographic extent
and impacts of saltwater encroachment into
coastal aquifers.
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Global warming may increase the intensity
and frequency of wildfires. Forest fires
can have adverse effects on climate change.
Fire
accounts for about 50% of greenhouse
gas emissions from deforestation and
about 20% of anthropogenic emissions
from report in the journal
Science. Besides the emissions
effect and reduced carbon sink
effect, a number of
criteria pollutants which can have a substantial
impact on human health. The fires will also
seriously affect future vegetation activities on
the same spot. |
According to the U.S. Drought Monitor (USDM),
nearly 8% of the United States (including
Alaska, Hawaii, and Puerto Rico) was
experiencing moderate to severe drought as of
March, 2010. Drought affected 57% of Hawaii's
land, with certain part of the Big Island moving
into exceptional drought for the first time
since 1999.
In 1997 and 1998
unprecedented forest fires broke out in
Indonesia. 24.1 million acres of forest were
destroyed, releasing 0.81 - 2.57 Gt of carbon
dioxide into the atmosphere. This is equivalent
to 13-40% of the mean annual global carbon
emissions from fossil fuels, and contributed
greatly to the largest annual increase in
atmospheric CO2 concentration
detected since records began in 1957.
The accompanying underground peat fires made it
almost impossible to put off the fire.
Consequential haze covered the neighboring
countries of Singapore, Malaysia, Sumatra, Sabah
and Sarawak, creating health hazards for months
before the fires were finally put off with
international help and efforts. There were many
other forest fires in Java and Sulawesi on the
same year.
Nature: Forest Fires in
Indonesia 1997
A report, Global Warming Contributes to
Australia's Worst Drought by WWF-Australia
and leading meteorologists has shown that
human-induced global warming was a key factor in
the severity of the 2002 drought. Comparison
with other major droughts found higher
temperatures caused a marked increase in
evaporation rates from soil,
watercourses and
vegetation.
Syrians head for cities
amid severe drought/ June 2010
A severe four-year drought is devastating
Syria’s rural communities, forcing them to head
for urban centers to seek for employment. The UN
estimates the mass exodus of migration amounts
to more than a million people, who simply were
not cultivating enough food or earning enough
money to sustain themselves. Prolonged drought
has caused the spread of a wheat crop disease
and disappointing wheat and cotton harvests.
Worst drought in Thailand
since years /June 2010
Thailand too is experiencing probably the
worst drought in the last 10 years. The drought
is affecting 9.6 million Thai farmers very badly
as more than 60% of the population depends on
agriculture. The drought is affecting 66 of
Thailand's 76 provinces, forcing local
authorities to stop supplying water for
irrigation. Alarmingly, the current water
supplies are not sufficient to have a second
dry-season crop cultivation this year.
The drought is
affecting other countries in South-east Asia.
Drought adds to Vietnam's Power Woes /June 2010
Vietnam is confronted with its worst water
shortage in decades, with the dry spell pushing
temperatures to a near 40°C, making the drought
the worst in a century. Water levels at the
reservoir was just above the “dead point”. This
had severely restricted output of power much
needed in Vietnam which is undergoing robust
economic development.
Cambodia
has called for international assistance.
Cambodia is suffering its second year of
drought, with the Mekong River water levels
dropping below normal levels, and many farmers
expect to lose their crops.
References and related
news:
China Struggles With Drought -
Feb 05 2009
Beijing (AFP)
Los Angeles: Worst Drought Ever Recorded -
Climate Progress
Brutal Drought Where It’s Normally We
- Climate
Progress
Warming Will Worsen Water Wars
- Climate Progress
