Ian James Diocese of Oxford E-mail. Environment Advisor [email protected] Climate change Revd Professor Ian James Head of School of Mathematics,

Ian James Diocese of Oxford E-mail . Environment Advisor [email protected]

Climate changeClimate change

Revd Professor Ian JamesHead of School of Mathematics, Meteorology &

Physics, University of Reading

Oxford Diocesan environment advisor

[email protected]


Plan of talkPlan of talk

• The problem

• Is climate change real?

• Some complications

• The future


The problemThe problem

- why climate change is a concern


Atmospheric carbon dioxideAtmospheric carbon dioxide


A little goes a long way!A little goes a long way!


Two views of EarthTwo views of Earth

Visible light Infra-red view


The “greenhouse” effectThe “greenhouse” effect

• Carbon dioxide blankets Earth’s surface.

• Sunlight gets in.

• Infra-red absorbed and re-emitted.

• Other greenhouse agents – water vapour, clouds.


Carbon dioxide & ice agesCarbon dioxide & ice ages


The carbon cycleThe carbon cycle

• Fossil fuels (coal, oil, natural gas) are made of carbon and hydrogen.

• When burnt, they produce energy, water and carbon dioxide.

Human Natural


What activities generate What activities generate carbon dioxide?carbon dioxide?

• All sources are comparable

• No easy target!• Reduction across

the board


Is climate change happening?Is climate change happening?

Some examples


Variations of the Earth’s surface temperature for the past 1,000 years

SPM 1b


Summer 2003Summer 2003

Deviation from 1961-1990 mean

Based on ECMWFand ERA-40

Color: temperature anomaly

Contours: normalized by standard deviation

(Schär et al. 2004, Nature, 427, 332-336)

ºC

Temperature Anomaly June-August 2003


HurricanesHurricanes

•More intense

•More extremes

•Form over hottest sea


Arctic sea iceArctic sea ice

September 1979 September 2005


Glaciers in retreatGlaciers in retreat

Pasterze glacier, Austria, 1875 Same view, 2004


Sea-level transgression scenarios for BangladeshSea-level transgression scenarios for Bangladesh

Adapted from Milliman et al. (1989).


Some complications….Some complications….


Feedbacks……Feedbacks……

A positive feedback loop…


Examples of climate feedbacksExamples of climate feedbacks

• Warm atmosphere becomes moister

• Melting ice & snow makes surface darker

• Melting tundra releases methane

• Moist atmosphere becomes cloudier


Melting permafrostMelting permafrost

• Vast areas of the high northern latitudes have permanently frozen soils – “tundra”.

• These are thawing out as warming accelerates

• Thawing releases methane• Methane is an even more

potent greenhouse gas than carbon dioxide


The “tipping point”The “tipping point”

• The point at which carbon dioxide levels are so high enough that feedbacks take over, and changes become irreversible.

• Are we approaching a “tipping point”?


The future?The future?


Global carbon emissions from fossil fuelsGlobal carbon emissions from fossil fuels


Only connect!Only connect!

• Interdependence of natural world

• We are part of natural world!

• Need to live sustainably within the entire world community

Ian James Diocese of Oxford E-mail. Environment Advisor [email protected] Climate change Revd Professor Ian James Head of School of Mathematics,

Documents

carbon dioxide levels

global carbon emissions

boardis climate change

natural gas

earths surface temperature

potent greenhouse gas

greenhouse agents water

temperature anomalycontours