Climate Change: Current State of Scientific Understanding Bob Watson

1
Climate ChangeCurrent State of Scientific
UnderstandingBob Watson
2
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

3
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

4
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

5
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
Projected changes from 1990 to 2100
Observed changes from 1976 to 1999
6
Slide 5 Precipitation
Projected changes in precipitation from 1990 to
2100
Observed changes in precipitation from 1900 to
2000
7
Slide 6 Most (greater than 50) of the Observed
Warming of the Last 50 Years is Attributable to
Human Activities
(b) observed and modeled changes disagree between
1920 and 1970 with anthropogenic forcing alone
(a) Observed and modeled changes disagree between
1950 and 2000 with natural forcing alone
(c) Observed and modeled changes in are in
good agreement with natural and anthropogenic
forcing
8
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

9
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 pre-industrial
  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

10
Slide 9 Climate Change

• Human-induced climate change is projected to
• Decrease water availability and water quality
  in many arid- and 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

11
Slide 10 Climate Change and Conflict

• Tens of millions of people displaced
• 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

12
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

13
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 (2013-2017) 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

14
Slide 13 Warming resulting from different
stabilized concentrations of greenhouse gases
pre-industrialized level - 280 ppm, current level
- 370 ppm

Temperature change relative to 1990 (C )
Even if the atmospheric concentration of carbon
dioxide was stabilized at todays level, the
Earths temperature would still increase by over
0.5oC The atmospheric concentration of carbon
dioxide equivalent (i.e., taking into account
other GHGs) is close to 450ppm. 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
10
Temperature change at equilibrium
9
8
76
5
4
3
2
1
0
450
550
650
750
850
950
1000
Eventual CO2 stabilisation level (ppm)
15
Slide 14 Conclusions from Exeter Meeting

• 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
  pre-industrial

16
 
Slide 15 Potential Actions
17
Slide 16 Policy Instruments

• 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 RD by governments and the private
  sector

18
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
• 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 todays 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

19
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 ST
• Innovative public-private partnerships and
  technology transfer are needed
• 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