global warming ‘political hype or reality?’

Global WarmingGlobal Warming‘Political hype or reality?’‘Political hype or reality?’ The Fernhurst Society The Fernhurst Society

- 5 April 2007 -- 5 April 2007 -

John Clement John Clement

Global warming - questionsGlobal warming - questions

What is happening?What is happening?

What are the reasons?What are the reasons?

What is likely to happen from now on?What is likely to happen from now on?

What can we do?What can we do?

What’s happening? Observable warmingWhat’s happening? Observable warming

Trending strongly above long-term averages Trending strongly above long-term averages since mid ‘70-ssince mid ‘70-s

NOTNOT the Earth’s long-term climate cycle the Earth’s long-term climate cycle

‘000 years before present

-

+ 5 -

0 -

- 5 -

-

This cycle is driven by Earth’s orbit changes

What’s happening? Consistent observationsWhat’s happening? Consistent observations

Similar trending since mid ‘70-s by three Similar trending since mid ‘70-s by three independent measuresindependent measures

What are the reasons? The climate systemWhat are the reasons? The climate system

What are the reasons? Radiation balanceWhat are the reasons? Radiation balance

Energy coming into the Earth Energy coming into the Earth from the Sun — SOLAR radiationfrom the Sun — SOLAR radiation

Energy leaving the Earth to outer Energy leaving the Earth to outer Space — INVISIBLE Space — INVISIBLE

INFRARED radiationINFRARED radiation

Solar radiation at poles and equatorSolar radiation at poles and equatorNear the poles, the Sun’s rays are spread out

over a wide area, so the heating is less intense

Near the equator, the Sun’s rays are spread out over a smaller area, so

the heating is more intense

The Earth’s climate systems in the atmosphere and oceans transport heat between the equator and the poles

- and produce the ‘weather’

SUN’S RAYS

Range of global temperaturesRange of global temperatures

What are the reasons? Is it solar radiation?

Implied changes in global tem

perature (°C)

What are the reasons? Solar radiation?What are the reasons? Solar radiation?

0.1

0.2

0

Solar radiation – has been Solar radiation – has been stablestable for the last for the last 50 years50 years

What is the reason? What is the reason?

Energy coming into the Earth Energy coming into the Earth from the Sun — SOLAR radiationfrom the Sun — SOLAR radiation

Energy leaving the Earth to outer Energy leaving the Earth to outer Space — INVISIBLE Space — INVISIBLE

INFRARED radiationINFRARED radiation

What is the reason? The ‘greenhouse’ effect?What is the reason? The ‘greenhouse’ effect?

What is the reason? The ‘greenhouse’ effect?What is the reason? The ‘greenhouse’ effect?

Greenhouse gas increases through Industrial Age Greenhouse gas increases through Industrial Age

COCO22 – roughly constant at 280 ppm until 1800 – – roughly constant at 280 ppm until 1800 – then rising rapidly to 380+ ppm today, and then rising rapidly to 380+ ppm today, and

further yet.further yet.

Methane – 800 ppb until 1800, Methane – 800 ppb until 1800, now 1,750 ppb.now 1,750 ppb.

Nitrous oxide 270ppb until 1800 – now 310 ppbNitrous oxide 270ppb until 1800 – now 310 ppb

Lower atmosphere ozone increased around 30% Lower atmosphere ozone increased around 30% over the same period.over the same period.

Greenhouse gases Greenhouse gases Predicted warming effect over the next 100 years Predicted warming effect over the next 100 years

Methane24%

Carbondioxide

63%

Nitrousoxide 10%

Others3%

CO2 is the major contributor CO2 is the major contributor

Volcanoes also affect the atmosphereVolcanoes also affect the atmosphere

Volcanic aerosols in the atmosphereVolcanic aerosols in the atmosphere

5

4

3

2

1

0

5

4

3

2

1

0

Estim

ated cooling effect, Wm

1883 Krakatau

1980

Mt. St. Helens

1991 Mt. Pinatubo

What’s happening? Observable warmingWhat’s happening? Observable warming

Trending strongly above long-term averages Trending strongly above long-term averages since mid ‘70-ssince mid ‘70-s

Suspected effect of atmospheric particulates

Climate models - improvingClimate models - improving

Natural factors alone do not explain the pattern of Natural factors alone do not explain the pattern of global warming since industrialisationglobal warming since industrialisation

COCO22 in the atmosphere – long term stability until in the atmosphere – long term stability until

industrialisationindustrialisation

The Industrial

Age

COCO22 from fossil fuels – rapid rise since 1950 from fossil fuels – rapid rise since 1950

Addition of man-made factors to models Addition of man-made factors to models

duplicates observationsduplicates observations

Q. Global Warming?Q. Global Warming?

Change between 1750 and 2000

A. Man-made gases dominateA. Man-made gases dominate

Global warming - questionsGlobal warming - questions

What is happening?What is happening?

What are the reasons?What are the reasons?

What is likely to happen from now on?What is likely to happen from now on?

What can we do?What can we do?

Global warmingGlobal warming

What is happening?What is happening?

What are the reasons?What are the reasons?

What is likely to happen from now on?What is likely to happen from now on?

What can we do?What can we do?

What is likely to happen from now on? What is likely to happen from now on?

Depends on what we do.Depends on what we do.

Slowing down GHG emissions, particularly carbon, Slowing down GHG emissions, particularly carbon, will mitigate future temperature rises – but there is a will mitigate future temperature rises – but there is a lot of momentum already embedded in the climate lot of momentum already embedded in the climate system. system.

Adaptation will be needed for coming changes in Adaptation will be needed for coming changes in – – rainfall patternsrainfall patterns- glaciers and sea-ice - glaciers and sea-ice - sea-levels - sea-levels - land temperatures- land temperatures- food crop, forest and animal ranges- food crop, forest and animal ranges- human impacts – livelihoods, wealth and health- human impacts – livelihoods, wealth and health

RainfallRainfall

Glaciers and sea-iceGlaciers and sea-ice

Sea levelsSea levels

Land temperaturesLand temperatures

Rainfall - changingRainfall - changing

UK precipitation by 2080sUK precipitation by 2080s

European summer rainfall outlook - 2080sEuropean summer rainfall outlook - 2080s

RainfallRainfall

Glaciers and sea-iceGlaciers and sea-ice

Sea levelsSea levels

Land temperaturesLand temperatures

Glaciers – meltingGlaciers – melting

16,700 in the world – 13,500 are in retreat16,700 in the world – 13,500 are in retreat

Gangotri glacier, Himalayas – a case studyGangotri glacier, Himalayas – a case study

Himalayan glaciers - criticalHimalayan glaciers - critical

Himalayan glaciers feed 7 of Asia’s great rivers

- The Ganges

- The Indus

- The Brahmaputra

- The Salween

- The Mekong

- The Yangtze

- The Yellow river

Himalayan glaciers - criticalHimalayan glaciers - critical

2.3 billion people

RainfallRainfall

Glaciers andGlaciers and Sea-ice Sea-ice

Sea levelsSea levels

Land temperaturesLand temperatures

Sea ice – also meltingSea ice – also melting

1.3 million km1.3 million km22 Arctic ice lost since mid-70s Arctic ice lost since mid-70s

Arctic sea-ice, maybe disappearing by 2080sArctic sea-ice, maybe disappearing by 2080s

West Antarctic and Greenland ice sheetsWest Antarctic and Greenland ice sheets

= 6m sea level rise = 7m sea level rise

1,000 years to melt , but……..

Oceans - The north Atlantic ConveyorOceans - The north Atlantic Conveyor

Hypothetical collapse in ocean currentsHypothetical collapse in ocean currents

Best forecasts of Atlantic circulationBest forecasts of Atlantic circulation– – its OK!its OK!

RainfallRainfall

Glaciers and sea-iceGlaciers and sea-ice

Sea levelsSea levels

Land temperaturesLand temperatures

Components of sea level riseComponents of sea level rise

Long-term momentum of sea-level risesLong-term momentum of sea-level rises

IPCC estimates of global mean sea-level riseIPCC estimates of global mean sea-level rise

North Sea storm surges by 2080North Sea storm surges by 2080

RainfallRainfall

Glaciers and sea-iceGlaciers and sea-ice

Sea levelsSea levels

Land temperaturesLand temperatures

European hot summers – human activity has European hot summers – human activity has roughly doubled the chancesroughly doubled the chances

European summer temperatures risingEuropean summer temperatures rising

2003

Global warming - questionsGlobal warming - questions

What is happening?What is happening?

What are the reasons?What are the reasons?

What is likely to happen from now on?What is likely to happen from now on?

What can we do?What can we do?

What can we do?What can we do?

Avoid unnecessary carbonAvoid unnecessary carbon

Be prudent with necessary carbonBe prudent with necessary carbon

Offset and seuester as much carbon as Offset and seuester as much carbon as possiblepossible

AdaptAdapt

COCO22 emissions reductions - the only emissions reductions - the only

route to stable concentrations.route to stable concentrations.C

O2 c

on

cen

trat

ion

(p

pm

) 750

650

550

450

350

2501990 2010 2030 2050 2070 2090

Year

◄ Pre-industrial concentration

Constant 1990emissions

Businessas usual

50% 1990emissions

No getting away from it – future warmingNo getting away from it – future warming

What can we do?What can we do?

Avoid unnecessary carbonAvoid unnecessary carbon

Be prudent with necessary carbonBe prudent with necessary carbon

Offset and sequester as much carbon as Offset and sequester as much carbon as possiblepossible

AdaptAdapt

Cross fingers for approx. 200 years!Cross fingers for approx. 200 years!

The EndThe EndThe Fernhurst Society The Fernhurst Society

- 5 April 2007 -- 5 April 2007 -

A presentation by John A presentation by John Clement Clement