climate change www.staff.uni-mainz.de/curtius/klimawandel CO 2 (ppm) 2007 Joachim Curtius Institut für Physik der Atmosphäre Universität Mainz Contents 1. Summary 2. Background 3. Climate change: observations 4. CO 2 5. OtherGreenhouse Gases (GHGs) 6. Aerosols and Clouds 7. Natural variability 8. Paleoclimate: glacials and abrupt climate change 9. Future climate change: feedbacks and uncertainties, consequences of climate chg. 10. Climate protection

feedbacks in the climate system feedbacks in the climate system: Non-linear, self-energizing or damping effects that influence climate. Main reason for uncertainties of climate sensitivity λ (" F = λ T"). Most importantexample of feedback mechanism: water vapor CO 2 greenhouse gas + temperature greenhouse gas + + + enhanced evaporation H 2 O (g) Enhancement of the effect by CO 2 by a factor of ~2

cloud radiative forcing associated with a CO 2 doubling according to several different climate models [IPCC 2001] large uncertainty and possibly "right for the wrong reasons" feedback mechanisms: ice-albedo effect for sea ice CO 2 [IPCC 2001]

consequences of climate change: shift of climatic zones extinction of species, reduced biological diversity coral reefs bleach out/die sea level rise increase of certain diseases (e.g. Malaria) effects on the hydrological cycle, freshwater supplies, forest fires, etc. climate driven natural desasters: heat waves, droughts, storms crop losses/decreased crop yields tourism insurance risks migration!? climate change and human health: net effect will be negative Increasing: heat wave victims flood victims tropical diseases like Malaria diseases in refugee camps Decreasing: cold victims

Vector-borne diseases Malaria and Dengue fever: Survival of parasites and mosquitos is temperature dependent; furthermore dependent on water Survival of natural enemies is also dependent on temperature, water, etc. Many other factors (non-climatic) such as development of health care are also very crucial.

increases in Malaria risk due to climate change:

IPCC WG3: Some of the poorest countries will be affected most strongly by climate change and these countries have the least financial resources to afford adaption and mitigation. biogenic diversity coral reefs: Hughes et al., Science, 2003, stress factors: increasing temperatures water quality overfishing/exploitation change of ph +1 C thermal stress leads to permanent bleaching of many coral species (corals expel zooxanthellae, their symbiotic pigmented microalgea) and often to complete extinction. very restricted adaption capabilities

changes of natural habitat: Thomas et al., Nature, 2004: "15-37% of all landliving species are 'committed to extinction' within the next 50-100 years due to climate change. climate change means additional stress for natural habitats, besides pollution, reduction by slashing and burning, etc. phenology... natural habitats cannot "move" change of natural habitats

change of natural habitats: phenology change of natural habitats foliation and foliage for common oak trees 9

"dangerous climate change" O'Neill et al., Science, 2002: increase of average surface temperature by: +1 C: coral reef bleaching. +2 C: possibility of melting of polar ice caps and sea level rise by several meters within a few centuries. Coastal regions with millions of inhabitants such as Bangladesh, Nile delta, parts of Florida become uninhabitable +3 C: potential of breakdown of THC. Maximum CO 2 concentration 450-550 ppm. climate protection: some keywords Kyoto protocol oil price trading emission certificates saving energy reducing deforestation technological solutions: renewables etc. CO 2 sequestration, fusion energy? Stern report: economic costs of climate change... action is required across all countries What to do? Can we do it? How much time is left to do it?

Broecker, CO 2 Arithmetic, Science, 2007 concept of CO 2 pie 760 Gt of C left to be burned, will lead to 560 ppm CO 2 in the atmosphere; rich countries have 150 Gt left to consume, 2 % decrease per year...

Kyoto protocol committments: promises and reality potentials for saving CO 2 emissions: population sufficiency = GDP/population energy efficiency substitution geoengineering

Fusion when? "50 years"... no problem with resources, pollution, disposal and accidents Fission/nuclear power plants disposal? accidents? terrorism? resources? 3rd world countries? not a global solution Wind energy already in place, will not cover the global demand... Offshore wind parks... Solar energy price, efficiency, etc. 13

What can be done by you? primary energy consumption of private households car hot water supply (natural gas) 6% heating (nat. gas) electricity 20% Germany: ~11 t CO 2 per capita per year cf.: a tree takes up ~40 kg CO 2 per year, plant 275 additional trees per person for balanced budget, 80 Mio. Germans = 22 Billion trees; 15 m 2 per tree, an area of 330 000 km 2 is needed, area of Germany: 352 000 km 2 heating regular house: 200-10 kwh/m 2 yr low energy house: 30-70 kwh/m 2 yr 1 l oil 1 m 3 nat. gas 10 kwh private electric power consumption: ~1600 kwh per capita know your own consumption... personal goal: -10% within 2 years, etc. Stromverbrauch pro Haushalt Heizverbrauch pro Haushalt

save energy! cars... houses: insulation, low energy,... warm water... cooking... appliances... travel... 20% CO 2 reduction announced by EU... but 40 new coal power plants in Germany in the next few years... but China opens a new coal power plant every other day... but Saudi Arabia offers energy intensive industry to settle there... a potential future scenario... [IPCC, SRCCS, 2005] a suite of combined measures will be necessary

To reduce CO 2 by a factor of 2 in a world of 9 billion people, then the average person is only allowed to burn ~500 kg C per year! Currently, "within a breath of history" we burn within a year what has been formed within 500 000 years

Many thanks! "climate change is the only thing that could bring our civilization to an end" Bill Clinton, World Economic Forum, Davos, 2006