Transcript THE FORECAST IMPACTS OF GLOBAL WARMING

What could we be facing in the years
ahead?
How will the Arctic and Africa be affected?
 Direct
impacts – environmental, social and
economic effects that occur in a specific
place due to temperature and rainfall
changes eg Arctic and Africa
 Indirect impacts – change that comes about
as a result of the temperature and rainfall
differences and this then causes impacts eg
sea level change
 +0.5
– 6.1°C - Falling crop yields in many
developing regions
 +1.5 – 3.8°C - Rising number of people at risk
from hunger (25 – 60% increase in the 2080s
in one study with weak carbon fertilisation),
with half of the increase in Africa and West
Asia
 +3.6 – 6°C - Yields in many developed regions
decline even if strong carbon fertilisation
 +4.1 – 5.8°C - Entire regions experience
major declines in crop yields (e.g. up to one
third in Africa)
+0.6 – 2.1°C - Small mountain glaciers disappear
worldwide - potential threat to water supplies in
several areas
 +2 – 4.3°C - Significant changes in water
availability (one study projects more than a
billion people suffer water shortages in the
2080s, many in Africa, while a similar number
gain water
 +2.1 – 3.8°C - Greater than 30% decrease in
runoff in Mediterranean and Southern Africa
 +4.2 – 5.9°C - Sea level rise threatens major
world cities, including London, Shanghai, New
York, Tokyo and Hong Kong
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 +0.4
– 2 °C - Coral reef ecosystems
extensively and eventually irreversibly
damaged
 +1.4 – 5.8 °C - Large fraction of ecosystems
unable to maintain current form
 +2 – 3.3 °C - Possible onset of collapse of
part or all of Amazonian rainforest
 +2.3 – 3.9°C - Many species face extinction
(20 – 50% in one study)
 +1
– 5.4°C - Rising intensity of storms, forest
fires, droughts, flooding and heat waves
 +2.2 – 3.9°C - Small increases in hurricane
intensity lead to a doubling of damage costs
in the US
 +1.5
– 3°C - Onset of irreversible melting of
the Greenland ice sheet
 +1.5 – 6°C - Risk of weakening of natural
carbon absorption and possible increasing
natural methane releases and weakening of
the Atlantic THC (Thermo Haline Circulation –
the global ocean currents)
 +3 – 6°C - Increasing risk of abrupt, largescale shifts in the climate system (e.g.
collapse of the Atlantic THC and the West
Antarctic Ice Sheet)
For < 1°C - It has been "recently suggested that
the threshold for an irreversible loss of the
Greenland ice sheet may be as low as 1°C".
 For 1–2°C - Climate models indicate the THC
begins to show signs of moderate weakening
 For 2–3°C - The THC weakens further, and
collapse of the Greenland or West Antarctic ice
sheets become even more likely
 For 3–4°C - Coral reefs suffer catastrophic failure
and the terrestrial biosphere becomes a net CO2
source
 By 4–5°C - The THC may be pushed to the point
of collapse
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36-37 Oxford
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52-54 Philip Allan
 P 46-47 Pearson and on CD ROM
 P 38-40 Oxford
Essay: The impact of global warming on the
Arctic
Include:
Impacts on the environment
Socio-economic impacts
Are there any benefits from global warming?
It is generally agreed that the Arctic will react
more strongly to global warming than any other
region, so in that sense it is both a barometer of
the impacts, and an early warning. Most models
estimate warming will be double the global
average in the Arctic.
 In addition, there are indigenous people, which
there are not in the Antarctic.
 The region is a zone of increasing resource
exploitation, and potential conflict, as fossil
fuels are minerals that run out.
 There is no ‘Arctic Treaty’ so the region is
potentially vulnerable to disagreement.
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Race to claim the Arctic
22 December 2007
From New Scientist Print Edition.
Rowan Hooper
 "This isn't the 15th century," exclaimed an indignant Canadian foreign minister.
"You can't go around the world and just plant flags and say: 'We're claiming this
territory'." Except that's exactly what Russia did in August when it audaciously
plonked a flag on the seabed under the North Pole, and lodged a claim of
sovereignty with the United Nations.
 Protestations apart, Canada has hardly been idle itself in the Arctic. In its own
show of strength, in July it announced it would spend a hefty US$7 billion
patrolling the Arctic Circle with icebreakers, and after Russia planted its flag,
Canada announced plans for a military training base on Nunavut in its far north.
 The dash to claim the "Arctic El Dorado" is well and truly on, and the reasons
why the race started in earnest in 2007 are twofold. First, the summer sea ice
melted more than ever. This means the prospect of plundering the Arctic seabed
for its riches of oil, gas and minerals is closer than ever. Similarly, the fabled
North-West Passage became navigable for the first time, which could slash
thousands of miles off the shipping route from Europe to Asia.
 The second reason is that claims to the Arctic shelf made under the UN
Convention on the Law of the Sea must be made within a decade of ratifying it,
so Russia only has until 2009, Canada until 2013, and Denmark until 2014.
 As the ice melts, the Arctic squabbling continues. Denmark says it has a claim to
the North Pole, via its self-governing province of Greenland. The Canadians say
the pole is theirs, while Russia has already set down its flag. Funny how there's
less clamour to preserve the ice than there is to plunder the riches beneath it.
Fears over the future of the Greenland Ice Cap.
Recent research suggests melting is increasing,
and the rate of melting is beyond the range of
most predictions.
 Fears over the loss of ecosystems associated
with the tundra. Whilst biodiversity is low,
within certain species groups it is very high;
Arctic flora and fauna cannot migrate north,
unlike lower latitude ecosystems.
 Fears that this vulnerable area will be the next
great resource frontier (see previous article)
adding to pressures from climate change.
 Concerns that culture and tradition among the
indigenous people will be swept aside as climate
change accelerates.
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 In
terms of indigenous people, the Arctic has a
population of about 4 million, but there are
numerous indigenous groups and sub-groups:
 Despite
much modernisation, many
indigenous people are still heavily
dependent, directly, on the natural
environment for some or all of their
resources. In this sense they are especially
vulnerable to change.
 3-4C
warming since the 1950s
 6-8C warming by 2100 considered a distinct
possibility
 Increased river discharge
 10% decline in snow cover since late 1970s
 10-20% decline in snow cover expected by
2070
 Precipitation increased 8% since 1900, mostly
as rain; further increases expected
 Permafrost has warmed by 2C since 1970s;
shifts northward of the permafrost zone of
100s km are expected.
Outbreaks of insects
Observed impacts - Spruce bark beetle is already on the rise; up to 2 million
hectares of spruce forest already damaged
Potential impacts - Likely to increase, as 2 year + hard frosts become rare and
beetle larvae survive
Forest fires
Observed impacts - Areas burned have doubled in western North America since the
1970s
Potential impacts - A further 80% increase in annual forest fires is expected by
2100
Agriculture
Observed impacts - Little impact so far
Potential impacts - Significant changes could increase growing seasons, allowing
more land to be converted to grazing
Polar Bears
Observed impacts - Growing concern over falling numbers in some regions
Potential impacts - An ice free Arctic could see populations crash, as bears rely on
ice for transport; populations used to isolation are unlikely to survive increasing
contact with Browns and Grizzlys
Ice dependent seals
Observed impacts - These are seals which give birth on sea ice, and
haul themselves onto sea ice e.g. ringed seals
Potential impacts - Similar to polar bears, many species so depend
on sea ice that their populations may become extinct.
Cod and Shrimp
Observed impacts - These fisheries have already been observed as
closely related to climate
Potential impacts - Cod populations could expand hugely as
climate warms, whereas shrimp populations are likely to crash
Tundra Plants
Observed impacts - Vegetations zones are already changing, with
and advance of forests and loss of grassland
Potential impacts - If permafrost continues to melt, long term
waterlogging will significantly change flora and insect life over
large areas, with knock-on effects to large mammals.
Ice crusting
Observed impacts - This occurs when unexpected winter thaws are
followed by fresh snowfall; this prevents Lemmings, Musk Ox and
Caribou from digging through the snow to forage
Potential impacts - Population collapses are highly likely due to
winter starvation
 The
arctic ecosystem is highly vulnerable as
it is deeply adapted to an intense, seasonal
climate. It relies upon a continuous, very
cold winter.
 There is evidence that this winter is fast
disappearing to be replaced by more
variable cold-thaw conditions which lead to
iceing, fails to kill pests, and promotes
waterlogging.
 Many species are not in a position to migrate
to new latitudes, and others which depend
directly on sea ice may simply disappear.
January 8, 2008 (New York Times)
In Greenland, Ice and Instability
By ANDREW C. REVKIN
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The ancient frozen dome cloaking Greenland is so vast that pilots have crashed into what they thought
was a cloud bank spanning the horizon. Flying over it, you can scarcely imagine that this ice could erode
fast enough to dangerously raise sea levels any time soon.
Along the flanks in spring and summer, however, the picture is very different. For a lengthening string of
warm years, a lacework of blue lakes and rivulets of meltwater have been spreading ever higher on the ice
cap. The melting surface darkens, absorbing up to four times as much energy from the sun as unmelted
snow, which reflects sunlight. Natural drainpipes called moulins carry water from the surface into the
depths, in some places reaching bedrock. The process slightly, but measurably, lubricates and accelerates
the grinding passage of ice toward the sea.
Most important, many glaciologists say, is the breakup of huge semis-ubmerged clots of ice where some
large Greenland glaciers, particularly along the west coast, squeeze through fjords as they meet the
warming ocean. As these passages have cleared, this has sharply accelerated the flow of many of these
creeping, corrugated, frozen rivers.
All of these changes have many glaciologists “a little nervous these days — shell-shocked,” said Ted
Scambos, the lead scientist at the National Snow and Ice Data Center in Boulder, Colo., and a veteran of
both Greenland and Antarctic studies.
Some fear that the rise in seas in a warming world could be much greater than the upper estimate of
about two feet in this century made by the Intergovernmental Panel on Climate Change last year. (Seas
rose less than a foot in the 20th century.) The panel’s assessment did not include factors known to
contribute to ice flows but not understood well enough to estimate with confidence. All the panel could
say was, “Larger values cannot be excluded.”
A scientific scramble is under way to clarify whether the erosion of the world’s most vulnerable ice sheets,
in Greenland and West Antarctica, can continue to accelerate. The effort involves field and satellite
analyses and sifting for clues from past warm periods, including the last warm span between ice ages,
which peaked about 125,000 years ago and had sea levels 12 to 16 feet higher than today’s.
The Arctic Council, representing countries with Arctic territory, has commissioned a report on Greenland’s
environmental trends, to be completed before the 2009 climate-treaty talks in Copenhagen, at which the
world’s nations have pledged to settle on a long-term plan for limiting human-caused global warming.
The National Oceanographic and Atmospheric
Administrations Arctic resource pages:
http://www.arctic.noaa.gov/

The IPCC 4th Assessment regional report chapter (15)
on impacts in the Polar Regions:
http://www.ipcc.ch/ipccreports/ar4-wg2.htm
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The Arctic Climate Impact Assessment (ACIA) 2005
http://www.acia.uaf.edu/
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The Arctic Council website
http://www.arctic-council.org/
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P55-56 Philip Allan
 P45-46 Pearson and on CD ROM
 P 41-43 Oxford
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Produce a power point presentation to answer
the exam question:
Why does climate change present potential
problems for the African continent?
Remember to include information about the
environmental, social, economic and political
effects
 Africa
makes the least contribution to global
warming worldwide
 However, it experiences a large number of
the consequences
 Predicted temperature change 4-5°C higher
than the global rate
 Rainfall is likely to increase in the equatorial
region, but decrease to the north and south
of that band.
Water Issues
 Water regulated by access to hydro-electric
power, domestic and industry
 Many of the larger rivers (River Nile) are
internationally shared – causing conflict
 Could lead to wars, global migrations and famine
Food Insecurity
 70% of population are subsistence farmers, many
of whom will not be able to feed themselves if
the water supplies dry up
 Increased locust plagues may also threaten food
supplies

Natural Resources
 Loss of biodiversity due to climate change will threaten
poorer people who are dependent on wildlife
Health
 Vector borne and water borne diseases could increase with
climate change
 80% of remedies rely on wild plants that are under threat.
Development of Coastal Zones
 60% of Africans live in coastal zones
 Make shanty towns in cities such as Accra, Freetown and
Lagos
 Coastal zones are at risk of coastal erosion and rising sea
levels
Desertification
 Major destroyer of grassland
 Increased by unreliable or decreasing rainfall