Observed and projected climate change – from global to local scale

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Helge DrangeGeophysical InstituteUniversity of Bergen

www.bjerknes.uib.no

Helge Drangehelge.drange@gfi.uib.no

Observed and projected climate change –from global to local scale

Helge DrangeGeofysisk institutt

Universitetet i Bergen

)CO2 in air (from Mauna Loa, Hawaii)

Universitetet i Bergen Ch

)Change in heat content of ocean & land+atm+ice

Universitetet i Bergen Ch

Change in heat content of ocean & land+atm+iceC

Earth´s climate is Earth´s climate is changingchanging

Main reason is our use of Main reason is our use of coal, oil and gascoal, oil and gas

Helge DrangeGeophysical instituteUniversity of Bergen

Possible futurePossible future

uncertainty ≠ no certainty

Change in global temperature, 15 models(relative to 1961-1990)

Future emissions as today (“Business-as-usual”)

+2 °C 2025-2050

In 2100:Global: 4.0-5.8 °CLand: 5.0-8.5 °C

Global emission top in 2040, 650 ppm CO2-eq in 2100

+2 °C 2035-2075

For a global, mean warming of ~2 °C, which we can expect sometime during second half of the 21st century, Earth's climate is comparable to

the climate ~3.2 mill years ago

In 2100:Global: 2.0-3.0 °CLand: 2.1-4.8 °C

Drought index based on 14 climate models(2090-2099; RCP4.5)

Dai, Nature Clim. Change (2012)

Severe to extreme drought

Incr soil moisture

Over to local scaleOver to local scale(where we all live)(where we all live)

Much harder to do local than continental/global climate projections!

Harder to make projections of precipitation than temperature

Very hard to make projections about local changes in extremes

Helge DrangeGeophysical InstituteUniversity of Bergen

Western Norway, 14 September 2005

14 Sep 2005

For Bergen: +30 to +70 %

increase in extreme precipitation by the end

of the century

Photo: Jan M. Lillebø, Bergens Tidende

Sea level

Warming of the oceanMay contribute 15-20 cm in this

century

Glaciers meltingMay contribute 15-20 cm in this

century

Greenland and AntarcticaMay contribute 10-40 cm in this

century (large uncertainties)

Total:+40 to +80 cm in 2100Cont’d increase “forever”

Department of GeophysicsUniversity of Bergen

Drange m.fl. (2012)

Estimated sea level rise (cm) along the coast of Norway, next 100 years

(corresponding to a global sea level rise of 50-110 cm)

About 1/3 of this rise by 2050

Sea levelWill last for > 1000 yr

2-degree target2-degree target

2-degree target:Consequence of delaying cuts in CO2-emissions

(i) CO2-emissions from coal, oil and gas, 1950-2012

Meinshausen et al. (2009), updated

(ii) Reduced CO2-emissions from 2013

) 2013: − 7 % / yr

(iii) Reduced CO2-emissions from 2017

2017: −11 % / yr

2013: − 7 % / yr

(iv) Reduced CO2-emissions from 2021

2021: −22 % / yr

2017: −11 % / yr

2013: − 7 % / yr

(v) Reduced CO2-emissions from 2025

2025: −90 % / yr

2021: −22 % / yr

2017: −11 % / yr

2013: − 7 % / yr

About 20 percentAbout 20 percentof today's COof today's CO22-emissions will -emissions will

remain in the atmosphere remain in the atmosphere for 1000 years or morefor 1000 years or more

Earthrise, 24 Dec 1968(credit: NASA)

Slides and animations available from

helge.drange@gfi.uib.no

Observed and projected climate change – from global to local scale

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