Put up yellow sun radiation slide draw how radiation is reflected as it hits the earth step by step on the black board
Variations of the Earth’s Surface Temperature: 1000 to 2100 The projected temperature changes from 2000 to 2100 for the 6 illustrative SRES scenarios are shown in comparison to temperatures observed over the last millennium. The “several models all SRES envelope” shows the temperature rise for the simple model when tuned to a number of complex models with a range of climate sensitivities. All SRES envelopes refer to the full range of 35 SRES scenarios.
Projected Changes in Annual Temperatures for the 2050s Although regional patterns are not projected with high confidence, land areas are projected to warm more than the oceans, higher latitude regions (regions closer to the poles) are expected to warm more than equatorial regions, and the Northern hemisphere is projected to warm more than the Southern hemisphere.
Climate Change Impacts The changes in temperature, precipitation patterns, and sea-level rise that have been observed and that are projected to occur will have wide-ranging and some potentially devastating impacts on the natural environment and human societies. [potential impacts are described in detail in TAR.4.Impacts.ppt] Our health, agriculture, forests, water resources, coastal areas, and species and natural areas are all vulnerable to the projected climate changes. For a small degree of warming, there is a mix of benefits and harms; harms increase dramatically for the higher projected temperature increases. Scientists have made estimates of the potential direct impacts on the various sectors listed here, but in reality the full consequences are more complicated because impacts on one sector can also affect other sectors indirectly. [Suggested transition to slides in next file: As scientists began to document warming and debate began over whether warming could be attributed to human activities and if so, what to do about it, this led to the formation of the Intergovernmental Panel on Climate Change (IPCC), and an international policy framework (United Nations Framework Convention on Climate Change) for dealing with the issue.]
Introduction to Climate Change Matt Spannagle [email_address] Bratislava, 14 March 2011
Well-understood principle that greenhouse gases trap heat in the atmosphere (Arhenius,1896)
Average temperature would be 33°C cooler without greenhouse effect
Greenhouse gases allow short wavelength ultraviolet (UV) and visible light from the sun to pass through the atmosphere, but absorb some of the heat re-emitted from the earth as longer wave length infrared radiation (IR)
Most processes that produce GHGs also produce other air pollutants
Reductions in related processes typically lead to the reduction in both but some reductions of one actually increase the other
Stratospheric ozone depletion
Ozone depleting substances (ODS) are generally powerful GHGs
Replacement of phased out ODSs with larger quantities of GHGs cancels beneficial effect of initial reduction on climate change (e.g. growth in HFCs due to phase out of CFCs)
Montreal Protocol – 1987, landmark international agreement to protect the ozone layer
Combined Annual Land-Surface Air and Sea Surface Temperature Anomalies (1861 to 2000, cf 1961 -1990). Two standard error bars shown on the annual number . Intergovernmental Panel on Climate Change. IPCC Third Assessment Report - Climate Change 2001: The Scientific Basis – Technical Summary. Geneva, 2001.
Northern Hemisphere Temperature Reconstruction (1000 to 2000) Intergovernmental Panel on Climate Change. IPCC Third Assessment Report - Climate Change 2001: The Scientific Basis – Technical Summary. Geneva, 2001.
Greenhouse Gas Concentrations in the Atmosphere IPCC Third Assessment Report - Climate Change 2001: The Scientific Basis – Technical Summary. Geneva, 2001.
Variations of temperature, CH 4 & atmospheric CO 2 Intergovernmental Panel on Climate Change. IPCC Third Assessment Report - Climate Change 2001: The Scientific Basis – Technical Summary. Geneva, 2001. CO 2 (2001) CH 4 (2001) (> 2X scale) Data derived from air trapped within ice cores from Antarctica
More recent - CO2 & Temperature Two standard error bars shown on the annual number . Intergovernmental Panel on Climate Change. IPCC Fourth Assessment Report - Climate Change 2007 2009: 387ppm
Up to this point - facts that are well understood, and not in dispute.
What does it mean for the future?
Modeled Variations of mean Earth’s Surface Temperature - 1000 to 2100
1000 to 1861, N. Hemisphere, proxy data
1861 to 2000, Global, instrumental
2000 to 2100, SRES projections
IPCC, TAR - Climate Change 2001: The Scientific Basis – Technical Summary. Geneva, 2001.
Global variability in Projected Changes in Annual Temperatures for the 2050s
… but reality is not average… mean <5% > 5% 15 o C 25 o C 35 o C 11 o C 25 o C 39 o C Historic ‘ average’ increase of 3 o C Average (3) + variability of 4 o C 22 o C 12 o C 32 o C Average + variability ‘ average’ increase May 1 st Historic
What we’re seeing….. NASA data for Jan-Apr 2010, 0.75 o C above 1951-80 base period
Moscow, August 2010. Hottest summer for at least 130 years, probably for last 1000 years, sparking forest fires and underground peat fires What we’re seeing…..