Climate Science Context
Brian Hoskins
Director Grantham Institute for Climate Change, Imperial CollegeProfessor of Meteorology, University of Reading
Kiehl and Trenberth 1997
The Earth’s energy budget
Green house gases: water vapour, carbon dioxide, methane, ozone,…
Fourier (1827), Tyndall (1861)
Kiehl and Trenberth 1997
The Earth’s energy budget
Extra GHGs: heat lost from higher levels where it is colder warming
Changes in Greenhouse gases in the atmosphere from Ice-Core and Modern Data
IPCC (2007)
Causes of the current imbalance in the energy budget
IPCC 2007
Published estimates of of NH Published estimates of of NH temperature in the past 1000 yearstemperature in the past 1000 years
Since 1970, rise in: Decrease in: Global surface temperatures NH Snow extent Tropospheric temperatures Arctic sea ice Global ocean temperatures Glaciers Global sea level Cold temperatures Water vapour Rainfall intensity Precipitation in extratropics Hurricane intensity Drought Extreme high temperatures Heat waves
IPCC 2007 Fourth Assessment Report: “Global Warming is unequivocal”
20th Century Continental Temperatures: Observed & Modelled with & without anthropogenic forcings
IPCC 2007
IPCC (2007) Surface Temperature Projections 2020s & 2090s relative to 1980-99
Global mean2020s 2090s
Stippled areas are where more than 90% of the models agree in the sign of the change
Precipitation increases very likely in high latitudes
Decreases likely in most subtropical land regions
This continues the observed patterns in recent trends
Projected patterns at end of 21st century: Change (%) in precipitation for one scenario
Dec-Feb June-Aug
IPCC 2007
© Crown copyright Met Office
Risk of large changes in ocean circulation and the release of methane cathrates
Risk of significant loss of rainforest. Few ecosystems can adapt.
Melting of Greenland ice sheet may become irreversible
Some marine ecosystems suffer irreversible change. Ocean acidification is already a risk.
+1 °C
+2 °C
+3 °C
+? °C
Dangerousclimatechange?
© Crown copyright Met Office
70 %99 %550 ppm
20 %80 %450 ppm
10 %60 %430 ppm
For 3 ºC target
For 2 ºC target
CO2 equivalent
stabilisation level
Percentage likelihood of warming exceeding 2 and 3 ºC above pre-industrial levels
Today
Stern target
Possible targets for stabilisation levels
Possible CO2 Emissions for 450ppm Stabilisation
10
15
20
25
30
35
40
45
2005 2010 2015 2020 2025 2030
Gt o
f CO 2
CCS in industryCCS in power generationNuclearRenewablesSwitching from coal to gasEnd Use electricity efficiency
End Use fuel efficiency
Reference Scenario
450 Stabilisation Case27 Gt
42 Gt
23 Gt
Energy-Related CO2 Emissions
© OECD/IEA 2007
RCEP (2000): Energy in a changing climate
Conclusion
•Adaptation •Mitigation•Geo-engineering?
Urgent need to really start
It is difficult to conceive that any significant reduction in the level of “dangerous” climate change realised by the end of the century can be achieved without CCS being a major player.
Greenland Ice Sheet Projections
MetO Hadley Centre
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