Costs and Benefits of Mitigation , Garnaut Review 2010

Possible Future without Climate Policy

Top panel: Fossil-fuel CO2 emissions for two scenarios: one “business as usual” [red] and

the other with net emissions peaking before 2020 and then reducing rapidly to near zero emissions by

2100, with the cumulative emission between 2000 and 2050 capped at 1000 billion tonnes of CO2 [blue].

Bottom panel: Median projections and uncertainties of global-mean surface air temperature based on

these two emissions scenarios out to 2100. The darkest shaded range for each scenario indicates the

most likely temperature rise (50% of simulations fall within this range). Adapted from Meinshausen et al.(2009)

Carbon Dioxide concentration

A Good Place to Start

From Climate Change (2007) The Physical Science Basis, a report accepted by 

Working Group I of the Intergovernmental Panel on Climate Change

Frequently Asked Questions

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Ozone concentrations

Stratospheric ozone has peak concentrations less than 8 ppm...

...which is a counterpoint to the view that atmospheric CO2
concentrations - currently 392 ppm - are not significant.

An Old Favourite...