Global Warming:

the Science, the Impacts

and the Politics

John Houghton

University of California, Irvine

20 February 2003

The Science of Global Warming

Variations of the Earth’s surface temperature

for the past 1,000 years

SPM 1b

The Greenhouse EffectSolar radiation

Long-wave radiation

Concentration of Carbon Dioxide and Methane Have Risen Greatly Since Pre-

Industrial TimesCarbon dioxide: 33% rise Methane: 100% rise

The MetOffice. Hadley Center for Climate Prediction and Research.

BW 5

The last 160,000 years (from ice cores) and the next 100 years

Time (thousands of years)160 120 80 40 Now

–10

0

10

100

200

300

400

500

600

700

CO2 in 2100(with business as usual)

Double pre-industrial CO2

Lowest possible CO2

stabilisation level by 2100

CO2 now

Temperature

difference

from now °C

CO

2 c

once

ntr

ati

on

(ppm

)

The Enhanced Greenhouse EffectSolar (S) and longwave (L) radiation in Wm-2 at the top of the atmosphere

S L

236 236

T = 18°C

S L

236 232

CO2 x 2

S L

236 236

CO2 x 2

S L

236 236

CO2 x 2+ Feedbacks

H2O (+60%) Ice/Albedo (+20%)

Cloud?Ocean?

TS = 15°C TS = 15°C TS ~ 1.2K TS ~ 2.5K

IPCC Synthesis Report

Estimated solar irradiance variations 1750-2000

Simulated annual global mean surface

temperatures

The climate system

The effect of the Mt. Pinatubo eruption (June 1991) on global temperature

The Impacts ofGlobal Warming

Contributions to sea level rise (metres), 1990-2100

ESTIMATED FOR IS92a SCENARIO

Thermal Expansion 0.28Glaciers 0.16Greenland 0.06Antarctica –0.01 TOTAL 0.49

Sea-level transgression scenarios for Bangladesh

Adapted from Milliman et al. (1989).

People at Risk from a 44 cm sea-level rise by the 2080s

Assuming 1990s Level of Flood Protection

Projected changes in annual temperatures for the 2050s

The projected change in annual temperatures for the 2050s compared with the present day, when the climate model is driven with an increase in greenhouse gas concentrations equivalent to about 1% increase per year in CO2

The MetOffice. Hadley Center for Climate Prediction and Research.

BW 11

1900 1920 1940 1960 1980 2000

5500500045004000350030002500200015001000500

0

Total use

Agricultural use

Industrial use

Domestic use

km 3/year

(from Shiklomanor (1988))

Global water use, 1900–2000

Irrigated cropland

appears red in this

satellite photograph,

made over the Nile where

it flows through the

Sudan. In the past 70

years, a variety of

irrigation projects have

increased the agricultural

productivity of this dry

region. More than half of

the increase in the

world’s agricultural

productivity during the

past few decades has

come from irrigation.

From PR Crosson and NJ Rosenberg, 1989

Changes in rainfall with doubled CO2 (CSIRO model)

>25.6

Daily rainfall class (mm day–1)

0.2-0.4 0.4-0.8 0.8-1.6 1.6-3.2 3.2-6.4 6.4-12.8 12.8-25.6

160

140

120

80

60

40

20

0

–20

100

Change infrequency

(%)

40°N 40°SAustralianlandpoints

Percent of the continental USA with a much above normal proportion of total annual precipitation from

1-day extreme events (more than 2 inches or 50.8mm)

Karl et al. 1996

BW 7

The 1997/98 El Niño - strongest on record

*As shown by changes in sea-surface temperature (relative to the 1961-1990 average) for the eastern tropical Pacific off Peru

El Niño years

La Niña years

BW 14

Country or region Refugees (millions)

Bangladesh 15Egypt 14China 30India

Other Delta Areas and Coastal Zones 10Island States 1Agriculturally-Dislocated Areas 50

Total 150

Country or region Refugees (millions)

Bangladesh 15Egypt 14China 30India

Other Delta Areas and Coastal Zones 10Island States 1Agriculturally-Dislocated Areas 50

Total 150

Estimate (after Myers) of environmental refugees in a greenhouse-affected world (by ~2050)

30

IPCC Synthesis Report

What can we do aboutGlobal Warming?

Intergovernmental Panel on Climate Change

Third Assessment Report 2001Scientific assessment includes:

Summary for Policymakers (SPM) 20 pages Technical Summary (TS) 60 pages 14 chapters 780 pages

prepared by 123 Co-ordinating Lead Authors & Lead Authors, 516 Contributing Authors, 21 Review Editors & 420 Expert Reviewers..

SPM agreed ‘line by line’ at Plenary Intergovernmental Meeting at Shanghai, January 2001, with delegates from 99 countries and 50 scientists representing the Lead Authors.

IPCC Website

•http://www.ipcc.ch

UNITED NATIONS FRAMEWORK CONVENTION ON CLIMATE CHANGE Rio de Janeiro : June 1992

ARTICLE 2: OBJECTIVEThe ultimate objective of this Convention .... is to achieve, .… stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.•Such a level should be achieved within a time-frame sufficient :• to allow ecosystems to adapt naturally to climate change.• to ensure that food production is not threatened, and • to enable economic development to proceed in a sustainable manner.

Global carbon emissions from fossil fuel

Global carbon emissions from fossil fuel use, 1850 to 1990, and for scenarios to 2100, in GtC.For each scenario, the range shows the difference between gross and net emissions.

From IIASA/WEC Global Energy Perspectives 1998.

Four Principles governing International Agreements

• Precautionary Principle • Principle of Sustainable

Development• Polluter Pays Principle • Principle of Equity

Carbon Emissions per capita per annum in 2000

(tonnes C)

USA 5.5 UK 2.5 China 0.7 India 0.3

World Average 1.0

Carbon dioxide contraction for 450 ppm & convergence

by 2030 to globally equal per capita emissions rights

Saving Energy in Buildings

• Use of white surfaces to reduce air conditioning

• Low-energy lighting

• Better insulation and control of space heating

• More efficient appliances

Important Energy Technologies• Renewable Technologies

– Wind – onshore & offshoreMarine – wave and tidalEnergy CropsEnergy from WastePV Solar

• Other Technologies– Combined Heat and Power– Carbon Sequestration– Fuel Cells– Hydrogen fuel infrastructure– Decentralised or Local Generation

Biomass

Car batteryRefrigerator

T.V.

Light Solar cell array

~1m2

~100 W peak power

Local solar energy supply

+ -

Surprise

Geoth.

Solar

Biomass

Wind

Nuclear

Hydro

Gas

Oil & NGL

Coal

Trad Bio.0

500

1000

1500

1860 1880 1900 1920 1940 1960 1980 2000 2020 2040 2060

exajoules

Energy Supply: Shell ScenarioSustained Growth Scenario

Source: Shell International Limited.

COST OF EMISSIONS REDUCTIONS

Estimated Cost of 60% reduction by 2050

On assumption of average economic growth at historic annual rate of 2.25%,

estimated loss of 0.02% from the growth rate

equivalent to loss of 6 months’ GDP growth over 50 yrs

UK govt Policy Innovation Unit Energy Review 2002 para 7.115

~1% GNP (DCs)~2-5% GNP (LDCs)

Plus other less quantifiable but important impacts

Move to Sustainable Consumption

<1% GNP

Cost of impacts ~1% GNP (DCs)~2-5% GNP (LDCs)

Plus other less quantifiable but important impacts

Action required

Energy efficiency and conservation

Change to non-fossil-fuel energy sources

Aforestation & Limit deforestation

Cost of action <1% GNP

GLOBAL WARMING

Global Warming Presents a Challenge to:

• scientists• industry and

technologists• governments • everybody

Message from Industry“No single company or country can solve the problem of climate change.It would be foolish and arrogant to pretend otherwise.But I hope we can make a difference - not least to the tone of the debate - by showing what is possible through constructive action.”

John Browne, BP, Berlin, 30 September 1997

Reasons for optimism

- Commitment of scientific community

- Necessary technology available

- God’s commitment to his creation

‘Nobody made a greater mistake than he who

did nothing because he could only do a little’

Edmund Burke