Transcript Agriculture as % of GDP 1993

Climate Change:
Current State of Scientific
Understanding
Bob Watson
Slide 1: Climate Change
• Climate change is both a development and global
environmental issue, which undermines:
• environmental sustainability
• poverty alleviation and the livelihoods of the poor
• human health
• national and regional security
• Climate change is an inter- and intra-generational
equity issue:
• developing countries and poor people in developing
countries are the most vulnerable
• the actions of today will affect future generations
because of the long life-times of the greenhouse
gases and the inertia within the climate system
Slide 2: Atmospheric composition
Since the industrial
era began,
human activities
have increased
the atmospheric
concentrations
of greenhouse
gases, which
tend to warm the
Earth, and sulfate
aerosols, which
tend to cool
the Earth, primarily
due to energy and
land management
practices
Slide 3: Climate Change
• The Earths climate has changed, in part due to
human activities, and is projected to continue
to change, globally and regionally:
• Warmer temperatures
• Changing precipitation
• Higher sea levels
• Retreating glaciers
• Reduced arctic sea ice
• More frequent extreme
weather events
•
heat waves, floods and droughts
Slide 4: Surface Temperature
A mid-range
projection of
change from 1990
to 2100 – a global
average of 3.1oC
The full projected
range for changes
in global average
temperature is
1.4oC to 5.8oC
Observed
changes from
1976 to 1999
Projected changes from 1990 to 2100
Slide 5: Precipitation
Projected changes
in precipitation
from 1990 to 2100
Observed changes
in precipitation
from 1900 to 2000
Slide 6: Most (greater than 50%) of the Observed
Warming of the Last 50 Years is Attributable to Human
Activities
(a) Observed and
modeled changes
disagree between
1950 and 2000 with
natural forcing alone
(c)
(b) observed and
modeled changes
disagree between
1920 and 1970
with anthropogenic
forcing alone
Observed and modeled changes in are in good agreement with
natural and anthropogenic forcing
Slide 7: Extreme Weather Events
Model Prediction
Confidence in
Observed Change

Higher maximum temperatures and more hot days
66-90%

Higher minimum temperatures, fewer cold days
and frost days over nearly all land areas
90-99%
Reduced diurnal temperature range over most
land areas
90-99%

Increased heat index over most land areas
90-99%

More intense precipitation events over many areas
90-99%

Increased summer continental drying and associated risk
of drought – mid-latitude continental interiors
66-90%

Slide 8: Recent Findings


Compared to the IPCC TAR, there is greater clarity and reduced
uncertainty about the impacts of climate change
A number of increased concerns have arisen:
• Increased oceanic acidity likely to reduce the oceans capacity to
absorb carbon dioxide and effect the entire marine food chain
• A regional increase of 2.7oC above present (associated with a
temperature rise of about 1.5oC above today or 2oC above preindustrial level) could trigger a melting of the Greenland ice-cap
• An increase in ocean surface temperature of 1oC is likely to lead to
extensive coral bleaching
• Reversal of the land carbon sink – possible by the end of the Century
• Possible destabilization of the Antarctic ice sheets becomes more likely
above 3oC – the Larson B ice shelve is showing signs of instability
• The North Atlantic Thermohaline Circulation may slow down or even
shut down: one study suggested that there is a 2 in 3 chance of a
collapse within 200 years, while another study suggested a 30%
chance of a shut down within 100 years
Slide 9: Climate Change
Human-induced climate change is projected
to:


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
Decrease water availability and water quality in many aridand semi-arid regions – increased risk of floods and droughts
in many regions
Decrease the reliability of hydropower and biomass
production in some regions
Increase the incidence of vector- (e.g., malaria and dengue)
and water-borne (e.g., cholera) diseases, as well as heat
stress mortality, threats nutrition in developing countries,
increase in extreme weather event deaths
Decrease agricultural productivity for almost any warming in
the tropics and sub-tropics and adverse impacts on fisheries
Adversely effect ecological systems, especially coral reefs,
and exacerbate the loss of biodiversity
Slide 10: Climate Change and
Conflict
• Tens of millions of people displaced

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Low lying deltaic areas
Small Island States
• Food shortages where there is hunger and famine
today
• Water shortages in areas already with water shortages
• Natural resources depleted (e.g., coral reefs, forests),
loss of ecological goods and services
• Increased incidence of disease
• Increased incidence of severe weather events
Climate Change, coupled with other local
and global environmental issues can lead to
local and regional conflict
Slide 11: The Kyoto Protocol
• All industrialized governments, except the US and Australia
have ratified the Kyoto Protocol, which contains:
•
A commitment to reduce GHG emissions, on average, by
about 5% between 2008-2012 relative to 1990
•
The flexibility mechanisms – carbon trading
•
Land-use, land-use change and forestry activities
•
Funding mechanisms to assist developing countries
• The US stated that the Kyoto Protocol was flawed policy because
it was neither fair nor effective and not in the best interests of the
US
• scientific uncertainties – Article 3 (precautionary principle)
• high compliance costs – inconsistent with IPCC
• ineffective without the participation of the large developing
countries
Slide 12: Beyond Kyoto
•
Without the US taking real action to limit their GHG emissions it is
doubtful that there will be a second commitment period – some
OECD countries will withdraw and large developing countries, i.e.,
China and India will not be willing consider any commitments
•
Without a commitment of governments to limit GHG emissions
beyond 2012 (the end of the first commitment period) the carbon
market will remain soft and the private sector is unlikely to enter
in a meaningful manner
•
The real question for governments is whether to:
• set an emissions target for a second commitment period (20132017) or whether to set a long-term stabilization target for climate
change (e.g., 2oC above the pre-industrial level)
• a 2oC target would require stabilizing the atmospheric equivalent
concentration of carbon dioxide at about 450ppm or less and
stabilization or decreases in the atmospheric concentrations of other
GHGs (see next slide)
• this would require a global emissions target – the challenge would
be to agree on intermediate emissions targets and an equitable
allocation of emissions rights
Slide 13: Warming resulting from different
stabilized concentrations of greenhouse gases
pre-industrialized level - 280 ppm, current level - 370 ppm
Even if the atmospheric concentration of
carbon dioxide was stabilized at today’s
level, the Earth’s temperature would still
increase by over 0.5oC
10
9
8
The atmospheric concentration of carbon
dioxide equivalent (i.e., taking into
account other GHGs) is close to 450ppm.
7
6
Temperature change
relative to 1990 (C )
Temperature
change at
equilibrium
5
The figure demonstrates that even if the
atmospheric concentration of carbon
dioxide was stabilized at 450-550 ppm, a
significant increase in temperature is
projected, thus adaptation is an
important part of a climate strategy
4
3
2
1
0
450 550 650 750 850 950 1000
Eventual CO2 stabilisation
level (ppm)
Slide 14: Conclusions from Exeter
Meeting
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Probability analysis suggests that to limit warming to 2oC above
pre-industrial levels with a relatively high certainty requires the
equivalent concentration of carbon dioxide to stay below 400ppm
Stabilization of the equivalent concentration of carbon dioxide at
450ppm would imply a medium likelihood of staying below 2oC
above pre-industrial levels
If the equivalent concentration of carbon dioxide were to rise to
550ppm it is unlikely that warming would stay below 2oC above
pre-industrial levels
The World Energy Outlook (2004) predicts that carbon dioxide
emissions will increase by 63% over 2002 levels by 2030. This
means that in the absence and urgent and strenuous actions to
reduce GHG emissions in the next 20 years, the world will almost
certainly be committed to a warming of between 0.5oC and 2oC
relative to today by 2050, i.e., about 1.1oC and 2.6oC above preindustrial
Slide 15: Potential Actions
Energy Efficiency and Conservation: Efficient vehicles, Reduced
use of vehicles, Efficient buildings, and Efficient coal plant
Fuel shift: Gas power for coal power
CO2 Capture and Storage: Capture CO2 at power plant; Capture CO2
at H2 plant; Capture CO2 at coal-to- synfuels plant; --- geological storage
Nuclear fission: Nuclear power for coal power
Renewable Electricity and Fuels: Wind power for coal power; PV
power for coal power; Wind H2 in fuel-cell car for gasoline in hybrid car;
Biomass fuel for fossil fuel
Forests and Agricultural Soils: Reduced deforestation, plus
reforestation, afforestation and new plantations; and Conservation tillage
Slide 16: Policy Instruments
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Policies, which may need regional or international
agreement, include:
• Energy pricing strategies and taxes
• Removing subsidies that increase GHG emissions
• Internalizing the social costs of environmental
degradation
• Tradable emissions permits--domestic and global
• Voluntary programs
• Regulatory programs including energy-efficiency
standards
• Incentives for use of new technologies during market
build-up
• Education and training such as product advisories and
labels

Accelerated development of technologies requires intensified
R&D by governments and the private sector
Slide 17: Key Scientific
Issues/Controversies
•There is growing consensus regarding the state of knowledge
regarding the science of climate change, but there remaining
uncertainties:
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What surprises could be in store – melting of the West Antarctic
or Greenland Ice Sheets, shut-down of the oceanic conveyor
belt, a non-linear response to greenhouse gas emissions?
What is the probability distribution around the climate
projections and what is the probability of limiting a change in
temperature to 2 degrees Celsius above pre-industrial for
different GHG stabilization levels?
The economic costs of action and inaction are highly debated,
hence there is a need to deepen our understanding of the
economic issues, i.e., the costs of action to mitigate climate
change and the costs of inaction on socio-economic sectors,
ecological systems and human health?
Are today’s energy production and use technologies adequate
to start to reduce GHG emissions cost-effectively - do we need a
revolution or an evolution in energy technologies to provide
affordable energy in a climate-friendly manner
Slide 18: Conclusions
•
•
•
Increased access to energy is critical for poverty alleviation and
economic growth
Climate change undermines development and environmental
sustainability
Access to affordable energy while also addressing climate change
will require a collaborative effort involving governments, private
sector, financial institutions, NGOs, and the research community
• Increased public and private sector funding for energy S&T
• Innovative public-private partnerships and technology transfer are
needed
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The Bank can play a critical role in assisting client countries
reduce GHG emissions and adapt to climate variability and change
Developing a robust carbon market can reduce emission reduction
costs in OECD and improve access to new technologies in
developing countries - carbon financing is a source of new
financing (non-ODA)
There are cost-effective and equitable solutions, but political will
and moral leadership is needed