Climate Change:Climate Change:Current State of Scientific Current State of Scientific

UnderstandingUnderstanding

Bob WatsonBob Watson

Slide 1: Climate ChangeSlide 1: Climate Change• Climate change is both a development and global Climate change is both a development and global

environmental issue, which undermines:environmental issue, which undermines:• environmental sustainabilityenvironmental sustainability• poverty alleviation and the livelihoods of the poorpoverty alleviation and the livelihoods of the poor• human healthhuman health• national and regional securitynational and regional security

• Climate change is an inter- and intra-generational Climate change is an inter- and intra-generational equity issue:equity issue:

• developing countries and poor people in developing developing countries and poor people in developing countries are the most vulnerablecountries are the most vulnerable

• the actions of today will affect future generations the actions of today will affect future generations because of the long life-times of the greenhouse because of the long life-times of the greenhouse gases and the inertia within the climate systemgases and the inertia within the climate system

Slide 2: Atmospheric compositionSlide 2: Atmospheric composition

Since the industrial Since the industrial era began,era began,human activitieshuman activitieshave increased have increased the atmospheric the atmospheric concentrations concentrations of greenhouse of greenhouse gases, which gases, which tend to warm the tend to warm the Earth, and sulfate Earth, and sulfate aerosols, which aerosols, which tend to cool tend to cool the Earth, primarily the Earth, primarily due to energy and due to energy and land management land management practicespractices

Slide 3: Climate ChangeSlide 3: Climate Change• The Earths climate has changed, in part due to The Earths climate has changed, in part due to

human activities, and is projected to continue human activities, and is projected to continue to change, globally and regionally:to change, globally and regionally:• Warmer temperaturesWarmer temperatures• Changing precipitation Changing precipitation • Higher sea levelsHigher sea levels• Retreating glaciersRetreating glaciers• Reduced arctic sea iceReduced arctic sea ice• More frequent extreme More frequent extreme

weather eventsweather events• heat waves, floods and droughtsheat waves, floods and droughts

Slide 4: Surface TemperatureSlide 4: Surface Temperature

Projected changes from 1990 to 2100Projected changes from 1990 to 2100

A mid-range A mid-range projection of projection of change from 1990 change from 1990 to 2100 – a global to 2100 – a global average of 3.1average of 3.1ooCC

The full projected The full projected range for changes range for changes in global average in global average temperature is temperature is 1.41.4ooC to 5.8C to 5.8ooCC

Observed Observed changes from changes from 1976 to 19991976 to 1999

Slide 5: Precipitation

Projected changes Projected changes in precipitationin precipitationfrom 1990 to 2100from 1990 to 2100

Observed changes Observed changes in precipitationin precipitation

from 1900 to 2000from 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 (a) Observed and modeled changes modeled changes disagree between disagree between 1950 and 2000 with 1950 and 2000 with natural forcing alonenatural forcing alone

((b) observed and b) observed and modeled changes modeled changes disagree between disagree between 1920 and 1970 1920 and 1970 with anthropogenic with anthropogenic forcing aloneforcing alone

((c) c) Observed and modeled changes in are in good agreement with Observed and modeled changes in are in good agreement with natural natural and anthropogenic forcingand anthropogenic forcing

Slide 7:Slide 7: Extreme Weather EventsExtreme Weather Events

Model PredictionModel Prediction Confidence in Confidence in Observed Observed

ChangeChange 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 Slide 8: Recent Findings Compared to the IPCC TAR, there is greater clarity and reduced Compared to the IPCC TAR, there is greater clarity and reduced

uncertainty about the impacts of climate changeuncertainty about the impacts of climate change

A number of increased concerns have arisen:A number of increased concerns have arisen:• Increased oceanic acidity likely to reduce the oceans capacity to Increased oceanic acidity likely to reduce the oceans capacity to

absorb carbon dioxide and effect the entire marine food chainabsorb carbon dioxide and effect the entire marine food chain

• A regional increase of 2.7A regional increase of 2.7ooC above present (associated with a C above present (associated with a temperature rise of about 1.5temperature rise of about 1.5ooC above today or 2C above today or 2ooC above pre-C above pre-industrial level) could trigger a melting of the Greenland ice-capindustrial level) could trigger a melting of the Greenland ice-cap

• An increase in ocean surface temperature of 1An increase in ocean surface temperature of 1ooC is likely to lead to C is likely to lead to extensive coral bleachingextensive coral bleaching

• Reversal of the land carbon sink – possible by the end of the CenturyReversal of the land carbon sink – possible by the end of the Century

• Possible destabilization of the Antarctic ice sheets becomes more likely Possible destabilization of the Antarctic ice sheets becomes more likely above 3above 3ooC – the Larson B ice shelve is showing signs of instabilityC – the Larson B ice shelve is showing signs of instability

• The North Atlantic Thermohaline Circulation may slow down or even 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 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% collapse within 200 years, while another study suggested a 30% chance of a shut down within 100 yearschance of a shut down within 100 years

Slide 9: Climate ChangeSlide 9: Climate ChangeHuman-induced climate change is projected Human-induced climate change is projected to:to:

Decrease water availability and water quality in many arid- Decrease water availability and water quality in many arid- and semi-arid regions – increased risk of floods and droughts and semi-arid regions – increased risk of floods and droughts in many regionsin many regions

Decrease the reliability of hydropower and biomass Decrease the reliability of hydropower and biomass production in some regionsproduction in some regions

Increase the incidence of vector- (e.g., malaria and dengue) Increase the incidence of vector- (e.g., malaria and dengue) and water-borne (e.g., cholera) diseases, as well as heat and water-borne (e.g., cholera) diseases, as well as heat

stress mortality, threats nutrition in developing countries, stress mortality, threats nutrition in developing countries, increase in extreme weather event deathsincrease in extreme weather event deaths

Decrease agricultural productivity for almost any Decrease agricultural productivity for almost any warming in warming in the tropics and sub-tropics and adverse impacts on fisheriesthe tropics and sub-tropics and adverse impacts on fisheries

Adversely effect ecological systems, especially coral reefs, Adversely effect ecological systems, especially coral reefs, and exacerbate the loss of biodiversityand exacerbate the loss of biodiversity

Slide 10: Climate Change and Slide 10: Climate Change and ConflictConflict

• Tens of millions of people displacedTens of millions of people displaced Low lying deltaic areasLow lying deltaic areas Small Island StatesSmall Island States

• Food shortages where there is hunger and famine Food shortages where there is hunger and famine todaytoday

• Water shortages in areas already with water shortagesWater shortages in areas already with water shortages• Natural resources depleted (e.g., coral reefs, forests), Natural resources depleted (e.g., coral reefs, forests),

loss of ecological goods and servicesloss of ecological goods and services• Increased incidence of diseaseIncreased incidence of disease• Increased incidence of severe weather events Increased incidence of severe weather events

Climate Change, coupled with other local Climate Change, coupled with other local and global environmental issues can lead to and global environmental issues can lead to

local and regional conflictlocal and regional conflict

Slide 11:Slide 11: The Kyoto ProtocolThe 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 KyotoSlide 12: Beyond Kyoto• Without the US taking real action to limit their GHG emissions it is Without the US taking real action to limit their GHG emissions it is

doubtful that there will be a second commitment period – some doubtful that there will be a second commitment period – some OECD countries will withdraw and large developing countries, i.e., OECD countries will withdraw and large developing countries, i.e., China and India will not be willing consider any commitmentsChina and India will not be willing consider any commitments

• Without a commitment of governments to limit GHG emissions Without a commitment of governments to limit GHG emissions beyond 2012 (the end of the first commitment period) the carbon beyond 2012 (the end of the first commitment period) the carbon market will remain soft and the private sector is unlikely to enter market will remain soft and the private sector is unlikely to enter in a meaningful mannerin a meaningful manner

• The real question for governments is whether to:The real question for governments is whether to:• set an emissions target for a second commitment period (2013-set an emissions target for a second commitment period (2013-

2017) 2017) oror whether to set a long-term stabilization target for climate whether to set a long-term stabilization target for climate change (e.g., 2change (e.g., 2ooC above the pre-industrial level)C above the pre-industrial level)

• a 2a 2ooC target would require stabilizing the atmospheric equivalent C target would require stabilizing the atmospheric equivalent concentration of carbon dioxide at about 450ppm or less and concentration of carbon dioxide at about 450ppm or less and stabilization or decreases in the atmospheric concentrations of other stabilization or decreases in the atmospheric concentrations of other GHGs (see next slide)GHGs (see next slide)

• this would require a global emissions target – the challenge would be this would require a global emissions target – the challenge would be to agree on intermediate emissions targets and an equitable to agree on intermediate emissions targets and an equitable allocation of emissions rightsallocation of emissions rights

Slide 13: Warming resulting from different Slide 13: Warming resulting from different stabilized concentrations of greenhouse gasesstabilized concentrations of greenhouse gases

pre-industrialized level - 280 ppm, current level - 370 ppmpre-industrialized level - 280 ppm, current level - 370 ppm

Even if the atmospheric concentration of Even if the atmospheric concentration of carbon dioxide was stabilized at today’s carbon dioxide was stabilized at today’s level, the Earth’s temperature would still level, the Earth’s temperature would still increase by over 0.5increase by over 0.5ooCC

The atmospheric concentration of carbon The atmospheric concentration of carbon dioxide equivalent (i.e., taking into dioxide equivalent (i.e., taking into account other GHGs) is close to 450ppm.account other GHGs) is close to 450ppm.

The figure demonstrates that even if the The figure demonstrates that even if the atmospheric concentration of carbon atmospheric concentration of carbon dioxide was stabilized at 450-550 ppm, a dioxide was stabilized at 450-550 ppm, a significant increase in temperature is significant increase in temperature is projected, thus adaptation is an projected, thus adaptation is an important part of a climate strategyimportant part of a climate strategy

Temperature change Temperature change relative to 1990 (C )relative to 1990 (C )

1010

99

88

7766

55

44

33

11

00450450 550550 650650 750750 850850 950950 10001000

Eventual COEventual CO22 stabilisation stabilisation level (ppm)level (ppm)

Temperature Temperature change at change at equilibriumequilibrium

22

Slide 14: Conclusions from Exeter Slide 14: Conclusions from Exeter Meeting Meeting

Probability analysis suggests that to limit warming to 2Probability analysis suggests that to limit warming to 2ooC above C above pre-industrial levels with a relatively high certainty requires the pre-industrial levels with a relatively high certainty requires the equivalent concentration of carbon dioxide to stay below 400ppmequivalent concentration of carbon dioxide to stay below 400ppm

Stabilization of the equivalent concentration of carbon dioxide at Stabilization of the equivalent concentration of carbon dioxide at

450ppm would imply a medium likelihood of staying below 2450ppm would imply a medium likelihood of staying below 2ooC C above pre-industrial levelsabove pre-industrial levels

If the equivalent concentration of carbon dioxide were to rise to If the equivalent concentration of carbon dioxide were to rise to 550ppm it is unlikely that warming would stay below 2550ppm it is unlikely that warming would stay below 2ooC above C above pre-industrial levelspre-industrial levels

The World Energy Outlook (2004) predicts that carbon dioxide The World Energy Outlook (2004) predicts that carbon dioxide emissions will increase by 63% over 2002 levels by 2030. This emissions will increase by 63% over 2002 levels by 2030. This means that in the absence and urgent and strenuous actions to means that in the absence and urgent and strenuous actions to reduce GHG emissions in the next 20 years, the world will almost reduce GHG emissions in the next 20 years, the world will almost certainly be committed to a warming of between 0.5certainly be committed to a warming of between 0.5ooC and 2C and 2ooC C relative to today by 2050, i.e., about 1.1relative to today by 2050, i.e., about 1.1ooC and 2.6C and 2.6ooC above pre-C above pre-industrialindustrial

Slide 15: Potential ActionsSlide 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 InstrumentsSlide 16: Policy Instruments Policies, which may need regional or international Policies, which may need regional or international

agreement, include:agreement, include:• Energy pricing strategies and taxesEnergy pricing strategies and taxes• Removing subsidies that increase GHG emissionsRemoving subsidies that increase GHG emissions• Internalizing the social costs of environmental Internalizing the social costs of environmental

degradationdegradation• Tradable emissions permits--domestic and globalTradable emissions permits--domestic and global• Voluntary programsVoluntary programs• Regulatory programs including energy-efficiency Regulatory programs including energy-efficiency

standardsstandards• Incentives for use of new technologies during market Incentives for use of new technologies during market

build-upbuild-up• Education and training such as product advisories and Education and training such as product advisories and

labelslabels Accelerated development of technologies requires intensified Accelerated development of technologies requires intensified

R&D by governments and the private sectorR&D by governments and the private sector

Slide 17: Key Scientific Slide 17: Key Scientific Issues/ControversiesIssues/Controversies

•There is growing consensus regarding the state of knowledge There is growing consensus regarding the state of knowledge regarding the science of climate change, but there remaining regarding the science of climate change, but there remaining uncertainties:uncertainties:

What surprises could be in store – melting of the West Antarctic What surprises could be in store – melting of the West Antarctic or Greenland Ice Sheets, shut-down of the oceanic conveyor or Greenland Ice Sheets, shut-down of the oceanic conveyor belt, a non-linear response to greenhouse gas emissions?belt, a non-linear response to greenhouse gas emissions?

What is the probability distribution around the climate What is the probability distribution around the climate projections and what is the probability of limiting a change in projections and what is the probability of limiting a change in temperature to 2 degrees Celsius above pre-industrial for temperature to 2 degrees Celsius above pre-industrial for different GHG stabilization levels?different GHG stabilization levels?

The economic costs of action and inaction are highly debated, The economic costs of action and inaction are highly debated, hence there is a need to deepen our understanding of the hence there is a need to deepen our understanding of the economic issues, i.e., the costs of action to mitigate climate economic issues, i.e., the costs of action to mitigate climate change and the costs of inaction on socio-economic sectors, change and the costs of inaction on socio-economic sectors, ecological systems and human health?ecological systems and human health?

Are today’s energy production and use technologies adequate Are today’s energy production and use technologies adequate to start to reduce GHG emissions cost-effectively - do we need to start to reduce GHG emissions cost-effectively - do we need a revolution or an evolution in energy technologies to provide a revolution or an evolution in energy technologies to provide affordable energy in a climate-friendly manneraffordable energy in a climate-friendly manner

Slide 18: ConclusionsSlide 18: Conclusions• Increased access to energy is critical for poverty alleviation and Increased access to energy is critical for poverty alleviation and

economic growtheconomic growth• Climate change undermines development and environmental Climate change undermines development and environmental

sustainability sustainability • Access to affordable energy while also addressing climate change Access to affordable energy while also addressing climate change

will require a collaborative effort involving governments, private will require a collaborative effort involving governments, private sector, financial institutions, NGOs, and the research communitysector, financial institutions, NGOs, and the research community

• Increased public and private sector funding for energy S&TIncreased public and private sector funding for energy S&T• Innovative public-private partnerships and technology transfer are Innovative public-private partnerships and technology transfer are

neededneeded• The Bank can play a critical role in assisting client countries The Bank can play a critical role in assisting client countries

reduce GHG emissions and adapt to climate variability and changereduce GHG emissions and adapt to climate variability and change• Developing a robust carbon market can reduce emission reduction Developing a robust carbon market can reduce emission reduction

costs in OECD and improve access to new technologies in costs in OECD and improve access to new technologies in developing countries - carbon financing is a source of new developing countries - carbon financing is a source of new financing (non-ODA)financing (non-ODA)

• There are cost-effective and equitable solutions, but political will There are cost-effective and equitable solutions, but political will and moral leadership is neededand moral leadership is needed