Climate ‘fix’ could deplete ozone Unit 3 Ideas in Context P7(H) Paper Paul Kerr The Derby High School, Bury

What is climate and weather? Climate – average weather conditions over a period of at least 30 years Weather – current conditions in the atmosphere, e.g. Rain. The Sun drives all of the Earth’s weather systems

Changing temperatures

Correlation? Temp & C02 level rising  Ice core evidence confirms similar changes in the past  Scientists know C02 warms the atmosphere  Computer models show global temperatures are related to rising C02 levels 

Cause? – The Greenhouse Effect

Changing Climates - Effects Natural factors Distance from the Sun changes Amount of radiation from the Sun changes in cycles Volcanic eruptions increase C02 levels Human factors Emission of greenhouse gases C02, CH4, H20 vapour

Changing Climates - Risks Melting ice (glaciers and ice caps) Rising sea levels (coastal changes) Extreme weather Effects on food and water resources Human health (e.g. Malaria) Financial (e.g. Insurance)

Changing Climates - Action Use the car less.... Turn the heating down.... Use non-fossil fuels.... Buy local produce.... Reduce air travel.... Recycle more... Avoid standby...

1991 Mount Pinatubo Eruption

Volcanic Cooling Sulfate (S02) particles reflect sunlight (Albedo) to counteract Global Warming Sulfates provide a surface on which chlorine gases in POLAR stratospheric clouds can become activated causing chemical reactions that destroy Ozone (03) molecules Atmospheric layers Ozone (03) protects us by absorbing harmful UV radiation. After the eruption of Mt Pinatube 03 decreased over Antarctica

Sulfate Injection Military jets and tanker aircraft or high altitude balloons could deliver sulfates into the stratosphere. Clouds form due to sulfate injection. Up to 90% reflection occurs, enhancing Albedo. Geo-engineering or climate-engineering is a deliberate method of changing the Earth’s climate to try to counteract Global warming

The Ozone Layer Ozone production Ozone absorbs dangerous UV radiation, protecting us below Ozone destruction Sulfates activate chlorine gases in polar clouds. Cl + O3 → ClO +O2 A free oxygen atom can release the chlorine atom to do further damage ClO + O → Cl +O2

Dr Simone Tilmes I measured O3 levels in the atmosphere and used computer simulations to estimate future 03 loss if sulphate injections continued Over the next 20yrs this could destroy as much as ¾ of the 03 layer over the Arctic Arctic – North Pole

Dr Simone Tilmes The expected recovery of ozone over Antarctic could also be delayed by about 30 to 70 yrs Antarctic – South Pole Sep 1979 Oct 2007 1987: Montreal Protocol. World agreement to ban CFC’s (Cl, F and C). 2050 fully repaired? (2080 – 2130?)

Dr Simone Tilmes More research is needed before society attempts global geo-engineering solutions in the future. We should not rule out this approach. Politicians will have to decide what is most important. They need to know what is good and bad about it.

Risks (bad) v Benefits (good) Sulfate injection Benefits Reduce Global Warming Risks Ozone depletion Holes in Ozone layer Increased UV exposure leading to increased cases of skin cancer Cancelling Sulfate injection Benefits Ozone layer protected Risks Global warming Melting ice caps and glaciers Rising sea levels Extreme weather Disease Financial costs ?