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CLIMATE CHANGE
UPDATE
Edexcel GCE Geography AS Unit 1
PowerPoint presentation with notes
January 2011
Climate change update 2010
PowerPoint outline
• Climate change and its causes
• The Impacts of global warming
• Coping with climate change
Climate change: the long-term evidence
Temperature rise
The longterm data
show natural
variability but a fairly
steady longterm trend.
In the last 100
years there is a
strong upwards
movement
away from the
established
trend.
Climate change: more evidence for change
Extreme events
• The 2010 floods in Pakistan left millions homeless and at
least one-fifth of the country under water.
• In Russia, the summer 2010 drought led to wildfires.
• Jeddah (Saudi Arabia) reached a high of 52°C in 2010.
• The UK had its heaviest snowfalls and coldest weather for
decades in December 2010.
• Extreme events of any single year cannot be taken as
definite proof of climate change.
• But most scientists say events in Pakistan and Russia in 2010
can be seen as consistent with climate change predictions.
Climate change: natural or human causes? (1)
Evaluating the evidence
Temperature rises and CO2 levels are always linked in the
historical record. CO2 levels are now their highest for 800,000
years. This coincides with unprecedented temperature rises.
Despite recent media controversy over aspects of how climate
change data have been handled by some scientists, humans are
almost certainly to blame for recent global warming.
Climate change: natural or human causes? (2)
Other influences at work ?
El Nino and
La Nina events
naturally last for
a few years and
cause weather
changes in many
places.
•The North Atlantic Oscillation is another climatic
phenomenon that may be linked with the recent
cold winter in the UK in 2010.
•Sunspot activity can lead to temperature change.
•But none of these explain recent global warming.
Climate change: unprecedented warming
Warming trends
Sea surface
temperatures
record a rise (this
might lead to more
hurricane activity).
Temperatures over
land are rising too.
(These trend lines
relate to the
recorded average
for 1960-1990.)
Arctic impacts of global warming (1)
Melting ice
The Artic is
heating twice
as fast as the
rest of the
world and
even faster
than models
predicted.
The region
may yet warm
by as much as
16°C !
Some years can
bring a minor
recovery of ice;
but the longterm trend is
greater
melting.
Impacts of global warming: sea-level rise
The causes
• Sea-levels around the UK have risen by 10 cm since 1900. Globally,
sea-levels is rising – the result of a warming climate in two
important ways:
• 1. Thermal expansion – as water warms it expands, like liquid in a
thermometer.
• 2. Melting land-based ice (but not sea ice – this has no effect).
Large amounts of water are locked on land in glaciers and
permafrost. Meltwater from this pours into oceans, raising levels.
• Global sea level rise of this kind is called a eustatic change.
• Local changes – such as land subsidence in delta regions – can
make the problem even worse.
Impacts of global warming: IPCC scenarios (1)
Temperature predictions
A wide range of predictions exist as a
result of IPCC 2007 and more recent
NOAA 2010 analysis. It is broadly
accepted by most scientists that a rise
of 1.5 – 4.0 °C is now inevitable.
Impacts of global warming: IPCC scenarios (2)
Changing precipitation
Warmer air holds
more moisture - so
precipitation may
rise in today’s
cooler places.
Areas that are already
arid may suffer even
lower rainfall. But
there is uncertainty
about how rainfall
patterns will change
overall.
Impacts of global warming: the tipping points
Albedo & methane
• ‘Tipping point’ effects are those that result in positive
feedback and an acceleration of changes like global warming.
• Loss of snow and ice cover could cause positive feedback (as
albedo values change and less and less sunlight is reflected).
• The release of methane, a potent greenhouse gas, from the
melting of the Arctic tundra could result in massively higher
carbon concentrations in the atmosphere, triggering a feedback
loop of warming temperatures melting more ice and releasing
more methane.
• The omission of potential feedback mechanisms from some
climate change models may lead to an underestimation of risk.
Coping with change: adaptation & mitigation
Different approaches
Adaptation and mitigation are the two
key responses; and there are also
different types of mitigation target.
Mitigation
means slowing global
warming by tackling the
underlying problem of the
build-up of GHG, e.g. by
switching to renewable
energy sources.
Adaptation
Carbon intensity
means dealing with
the consequences of
climate change, for
instance by
strengthening flood
defences.
is a measure of how much
carbon dioxide is produced in
relation to GDP. A country like
China whose GDP is rising can
partially mitigate by decreasing
the carbon intensity of its GDP
as that figure rises - but total
emissions still rise.
Coping with change: a global agreement (1)
Pre-Kyoto
• Global concern about climate change has been mounting since
the late 1980s.
• In 1988, the UN Environmental Programme and the World
Meteorological Organisation set up the Inter-governmental Panel
on Climate Change (IPCC).
• At the 1992 Earth Summit in Rio, 190 countries signed a treaty
agreeing that the world community should ‘achieve stabilisation
of greenhouse gas concentrations’.
• In 1997, world leaders met again in Kyoto in order to develop the
treaty further into a more detailed biding agreement known as a
protocol.
Coping with change: a global agreement (2)
Kyoto
• The Kyoto Protocol required all signatories to agree to a legally
binding GHG emissions reduction target. For instance, the official
EU target was 8%, a goal later increased to 20% by 2020.
• It failed to achieve its full effect partly because it was not
originally supported by the USA.
• The exemption of emerging economies from seeking binding
targets became a serious weakness when China overtook the USA
to become the world’s largest carbon emitter.
• The Kyoto Protocol expires in 2012. Any new pact will be groundbreaking if it can bring together for the first time developed and
rapidly emerging economies with legally binding targets to reduce
greenhouse gas emissions.
Coping with change: a global agreement (3)
Copenhagen & Cancún
• At the 2009 Copenhagen summit, developed and developing
country governments agreed to try to prevent temperatures
rising more than 2°C above pre-industrial levels.
• But the pledges made were not legally binding.
• Talks in Cancún took the accord reached at Copenhagen a stage
further. Countries agreed: to try and set up a “green fund” that
will distribute money to help poor countries cope with climate
change; increased international co-operation on low-carbon
technology; more help for developing nations preserve their
forests.
Coping with change: roles of key players
Carbon stock and flow
In 2005, much of
the extra CO2
already added to
Earth’s
atmosphere has
come from
developed
countries. This is
called the carbon
stock. Developing
countries are not
as responsible for
this legacy.
Between 2005
and 2030,
much of the
new CO2
being
produced will
come from
developing
countries –
this is called
the carbon
flow.
Coping with change: views of key players
Superpower pledges
Pledges of the global superpowers
European Union
has made a
binding pledge
to cut its
emissions by
20% by 2020
(compared with
1990 levels).
United States
Is still the
world’s second
biggest carbon
dioxide emitter,
producing 5,900
million tonnes of
CO2 (e) each
year. No binding
pledge yet.
China has a
2020 target to
reduce the
carbon intensity
of its fastgrowing GDP.
GHG emissions in
2020 will be 40%
higher than
today, but lower
than they might
otherwise be.
India has set a
non-binding
target of 24%
reduction in
emissions
intensity is
sought by 2024,
equal to savings
of nearly 2000
mtCO2(e).
Coping with climate change: progress report
Technological fix needed ?
• “BY 2030, three-quarters of all humankind may have moved to the cities.
An estimated 3 billion will live in slums without access to sanitation, clean
water, public transport, medical clinics or schools. Their lives are likely to
be neither comfortable nor – if the link between extremes and climate
change is a real one – long. Six of the planet's 10 most populous cities are
already vulnerable to cyclone, flood or tsunami. But extremes of heat,
and the consequent increase in urban air conditioning, are likely to make
future heat-waves even more lethal.” (Guardian newspaper)
• “The world is neither willing nor able to go cold turkey when it comes to
ending its addiction to fossil fuels. The problem, particularly for China,
India, and the rest of the developing world, is that there simply are not
any affordable alternatives. We need to increase spending on green-energy
research by a factor of 50.” (Bjørn Lomborg, director of the Copenhagen
Consensus Centre)
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Data from Met Office
Illustrations from Financial Times (with permission)
Reporting from Financial Times & Guardian
http://www.ft.com/cms/s/0/5b76b578-04d3-11e0-a99c00144feabdc0.html#axzz19zSp4IH8
http://www.ft.com/cms/s/0/72993406-b398-11df-81aa00144feabdc0.html#axzz19zMi0HaR
http://www.ft.com/cms/s/0/ec28be44-061e-11e0-976b00144feabdc0.html#axzz19zSh9NLP