The Science of Climate ChangeThe Science of Climate Change

Jeff LewisJeff Lewis

Where do we learn about global warming?

The Media!

Tuesday, January 23, 2001

Sunday, January 14, 2001

Good InformationGood InformationIntergovernmental Panel on Climate Change (IPCC)Intergovernmental Panel on Climate Change (IPCC) www.ipcc.chwww.ipcc.ch

Environment CanadaEnvironment Canada

http://www.ec.gc.cahttp://www.ec.gc.ca

Arctic Climate Impact Assessment (ACIA)Arctic Climate Impact Assessment (ACIA)

www.amap.no/acia/index.htmlwww.amap.no/acia/index.html

Kyoto ProtocolKyoto Protocol

unfccc.int/resource/convkp.htmlunfccc.int/resource/convkp.html

OverviewOverview

What is climate change and global warming?What is climate change and global warming? Recent history of climate changeRecent history of climate change Anthropogenic (human induced) climate changeAnthropogenic (human induced) climate change Projections of future climate changeProjections of future climate change Climate feedbacksClimate feedbacks The Kyoto ProtocolThe Kyoto Protocol A climate success storyA climate success story

““Climate is what you expect,Climate is what you expect,

weather is what you get”weather is what you get”

Climate is the “average weather”

Climate Change is a “change in the average weather”

Global Climate Change will affect different regions of the world in different ways

What is Climate Change?What is Climate Change?

What is Global Warming?What is Global Warming? Increase in Earth’s mean temperature due to an increase

in atmospheric greenhouse gases Increasing C02 amplifies the greenhouse effect

Enhanced greenhouse effect

Temperature anomalies in the Northern Hemisphere over the last 1000 years

Medieval Warm Period

Little Ice Age

Norse settlement of Greenland (980)

Norse western settlement of Greenland abandoned

(1350)

Recent History of Climate Change

Temperature anomalies in the Northern Hemisphere over the last 1000 years

Medieval Warm Period

Little Ice Age

The great famine (1315-21)

Pieter Bruegel (1565)

Recent History of Climate Change

The Hunters in the Snow, Pieter Bruegel, 1565

CO2 = 375 ppm

A 420,000 year record of COA 420,000 year record of CO22, CH, CH44 and inferred and inferred Antarctic TemperatureAntarctic Temperature

CH4 = 1750 ppb

Long-Term Temperature TrendsLong-Term Temperature Trends

Over the last Over the last 1000yrs the 1000yrs the global mean global mean temperature was temperature was decreasing until decreasing until the 1900sthe 1900s

1: 1998 2: 20033: 20024: 20015: 19976: 19957: 19908: 19999: 200010: 1991

THE TOP 10

Warming over the last 100 years

Intergovernmental Panel on Intergovernmental Panel on Climate Change (IPCC)Climate Change (IPCC)

Established by the World Meteorological Organization (WMO) and the United Nations Environment Program (UNEP) in 1988

Does NOT carry out research or monitor climate data

Undertakes an assessment of the peer-reviewed scientific literature www.ipcc.ch

Working Group I (WGI): Science

Working Group II (WGII): Socioeconomic impacts and adaptation Working Group III (WGIII): Mitigation

IPCC Summary for Policy Makers IPCC Summary for Policy Makers (Working Group I)(Working Group I)

IPCC 1996IPCC 1996

“The balance of evidence suggests a discernible human influence on global climate”

IPCC 2001IPCC 2001

“There is now new and stronger evidence that mostof the warming observed over the last 50 years

is attributable to human activities”

Can models reproduce the climate Can models reproduce the climate of the 20th Century?of the 20th Century?

ObservationsModel

Anthropogenic Climate ChangeAnthropogenic Climate Change

Greenhouse Gases

Main Greenhouse Gases

H2O – Water VapourCO2 – Carbon DioxideCH4 – MethaneN2O – Nitrous OxideO3 – Ozone (Troposphere)CFCs – Chloro-fluorocarbons

Longwave Absorption Band

N2O

O3

CO2

H2O

Contribution to the Greenhouse EffectContribution to the Greenhouse Effect(including water vapor)(including water vapor)

Water vapourWater vapour is the most is the most dominant dominant greenhouse greenhouse gasgas

Contribution to the Greenhouse EffectContribution to the Greenhouse Effect(without water vapour)(without water vapour)

Carbon dioxide is the second is the second most dominant most dominant greenhouse greenhouse gasgas

Carbon dioxide

CO2 5 -200 1 1

Methane CH4 12 62 23

Nitrous Oxide

N2O 114 275 296

HFC -23 CHF3 260 9400 12000

Gas Lifetime

(years) 20 yrs 100 yrs

Global Warming PotentialGlobal Warming Potential

Direct Global Warming Potential Direct Global Warming Potential relative to carbon dioxiderelative to carbon dioxide

Greenhouse GasesGreenhouse Gases

Highest amount of greenhouse

gases in last 1000 years

Carbon DioxideCarbon Dioxide

MethaneMethane

Nitrous OxideNitrous Oxide

Greenhouse GasesGreenhouse Gases

Carbon Dioxide

Methane

Nitrous Oxide

Greenhouse Gas EmissionsGreenhouse Gas Emissions

In CanadaIn Canada

What about concentrations What about concentrations in the year 2100?in the year 2100?

CO2 = 486–1248 ppm

CH4 = 1750–3731 ppb

The influence of humans on climate evolution

Land-Use Change

Loss of vegetation burning

releases CO2

Leads to warming

More reflective ground

less sunlight absorbed

Leads to cooling

Projections of future climateProjections of future climateThe Emissions Scenarios

Carbon DioxideEmissions

AtmosphericSulphur DioxideConcentration

AtmosphericCarbon DioxideConcentration

Also done for other greenhouse gases (methane, nitrous oxide etc)

Projections of future climate Projections of future climate — Year 2100— Year 2100

Global Mean Temperature Global Mean Sea Level

1.4 – 5.8°C increase 9 – 88 cm increase

Projections of future climate Projections of future climate (Annual Mean Temp. Change)(Annual Mean Temp. Change)

Years 2071–2100 relative to years 1961–1990

Climate FeedbacksClimate FeedbacksWater VapourWater Vapour (positve feedback)(positve feedback)

Temperature increasesTemperature increases

More evaporationMore evaporation

More water vapour in the atmosphereMore water vapour in the atmosphere

EnhancedEnhancedgreenhousgreenhouse e effecteffect

AtmosphereAtmosphere

LandLand

OceanOcean

More H2O

Climate FeedbacksClimate FeedbacksIce albedo feedbackIce albedo feedback (positve feedback)(positve feedback)

Temperature increasesTemperature increases

More radiation More radiation is absorbedis absorbed

Reveals darker surfaceReveals darker surface

Ice meltsIce melts

Climate FeedbacksClimate FeedbacksCloud feedbacksCloud feedbacks1)1) Positive feedbackPositive feedback

Temperature increasesTemperature increases

More water vapourMore water vapour

More outgoing longwave radiation is absorbedMore outgoing longwave radiation is absorbedlongwave radiationlongwave radiation

Climate FeedbacksClimate FeedbacksCloud feedbacksCloud feedbacks2)2) Negative feedbackNegative feedback

Temperature increasesTemperature increases

More water vapourMore water vapour

More incoming shortwave radiationMore incoming shortwave radiation is reflectedis reflected

shortwave radiationshortwave radiation

Less incoming shortwave radiation is absorbedLess incoming shortwave radiation is absorbed

Temperature decreasesTemperature decreases

Climate FeedbacksClimate FeedbacksCloud feedbacksCloud feedbacks Overall EffectOverall Effect

UnknownUnknown

Impacts of Global WarmingImpacts of Global Warming

Amplified warming at high latitudesAmplified warming at high latitudes Amplified warming in N. HemisphereAmplified warming in N. Hemisphere Amplified warming over landAmplified warming over land Increased winter precip. at mid-high Increased winter precip. at mid-high

latitudeslatitudes Increased likelihood of summer droughtIncreased likelihood of summer drought Increased likelihood of extreme eventsIncreased likelihood of extreme events Retreat of glaciers and sea iceRetreat of glaciers and sea ice

Impacts on CanadaImpacts on Canada Flooding and erosion in coastal areasFlooding and erosion in coastal areas Forests at risk from pests and droughtForests at risk from pests and drought Environmental changes may harm plant Environmental changes may harm plant

and animal lifeand animal life Decrease in quality of drinking waterDecrease in quality of drinking water More severe and frequent extreme weatherMore severe and frequent extreme weather Changes to fishery habitats and populationsChanges to fishery habitats and populations Possible benefit to agriculture industryPossible benefit to agriculture industry

Glaciers MeltingGlaciers Melting

Wedgemont Glacier, Whistler BC

20 glacier length records from different parts of the world

Fig 2.18 (IPCC Report 2001)

Glacier locationsGlacier locations

Sea level rise 1910-1990

(IPCC Report 2001)

Warming of the Oceans

Thermal expansion

Freezing Point

As water heats As water heats it expandsit expands

If Greenhouse gas concentrations were stabilized, sea level would nonetheless continue to rise for hundreds of years!

(after 500 years, sea level rise from thermal expansion may have reached only half of its

eventual level)

21% of the world’s population live within 30 km of a shoreline

Large coastal cities and agglomerations at the start of

the 21st century (8 million people and above)

The Kyoto ProtocolThe Kyoto Protocol

The Kyoto Protocol was adopted in Kyoto, Japan, The Kyoto Protocol was adopted in Kyoto, Japan, on 11 December 1997 under theon 11 December 1997 under the United Nations United Nations Framework Convention on Climate Change. Framework Convention on Climate Change.

The goal of the Kyoto Protocol is to cut the total The goal of the Kyoto Protocol is to cut the total greenhouse-gas emissions by at least 5% from greenhouse-gas emissions by at least 5% from 1990 levels in the commitment period 2008-20121990 levels in the commitment period 2008-2012

The Kyoto ProtocolThe Kyoto Protocol

For CanadaFor Canada

Cut emissions to Cut emissions to 6% less than 6% less than 1990 emissions1990 emissions

Kyoto will now Kyoto will now

be legalbe legal

The effect of KyotoThe effect of KyotoGlobal mean temperature Global mean sea level

Warming(°C)

Sea LevelRise (cm)

• We all do nothing: 2.08 50.0

The Policy Action

• We all meet Kyoto targets but do no more: 2.00 48.5

• We all meet Kyoto targets and meet a 1%/year further reduction in emissions after 2010:

1.80 45.5

Reductions Required for StabilisationReductions Required for Stabilisation

To stabilise the atmospheric concentration of CO2 at nearly 4 times preindustrial levels, emissions need to be cut by ~50% of 1990 levels globally

A Climate Success StoryA Climate Success Story

The 1987 Montreal Protocol and CFCs