The greenhouse effect and global warming What are they? The causes, effects, impacts and responses

THE NATURAL GREENHOUSE EFFECT The atmosphere has a number of gases, often in tiny amounts, which trap the heat given out by the Earth. To make sure that the Earth's temperature remains constant, the balance of these gases in the atmosphere must not be upset.

The GREENHOUSE GASES are very important and are mainly: water vapour occurs naturally in the atmosphere. carbon dioxide produced naturally when people and animals breathe. Plants and trees absorb carbon dioxide to live. Volcanoes also produce this gas. Carbon dioxide is not the same as carbon monoxide methane comes from cattle as they digest their food. The gas also comes from fields where rice is grown in paddy fields. nitrous oxide when plants die and rot, nitrous oxide is produced. ozone occurs naturally in the atmosphere.

THE ENHANCED GREENHOUSE EFFECT Because there are more and more greenhouse gases in the atmosphere, more heat is trapped which makes the Earth warmer. This is known as global warming. A lot of scientists agree that man's activities are making the natural greenhouse effect stronger. If we carry on polluting the atmosphere with greenhouse gases, it will have very dangerous effects on the Earth.

What are the causes of rises in Greenhouse gases

THE ENHANCED GREENHOUSE EFFECT Some of the activities of man also produce greenhouse gases. These gases keep increasing in the atmosphere. The balance of the greenhouse gases changes and this has effects on the whole of the planet. Burning fossil fuels - coal, oil and natural gas - releases carbon dioxide into the atmosphere. Cutting down and burning trees also produces a lot of carbon dioxide. A group of greenhouse gases called the chlorofluorocarbons, - which are usually called CFCs, because the other word is much too long! - have been used in aerosols, such as hairspray cans, fridges and in making foam plastics. They are found in small amounts in the atmosphere. They are dangerous greenhouse gases because small amounts can trap large amounts of heat.

Methane is x 30 more effective than CO2 Where does methane come from Methane is x 30 more effective than CO2 Where does methane come from? (3 places) Some greenhouse gases X 300 more effect on global warming than CO2 Man-made sources of nitrous oxide include nylon and nitric acid production, the use of fertilisers in agriculture, cars with catalytic converters and the burning of organic matter.

CO2 and temperature rise

Two ways of looking at causes

The effects

Global Warming – some effects Since 1970, rise in: Decrease in: Global surface temperatures NH Snow extent Tropospheric temperatures Arctic sea ice Global Sea Surface Temperatures Glaciers Global sea level Cold temperatures Water vapor Rainfall intensity Precipitation extratropics Hurricane intensity Drought Extreme high temperatures Heat waves

Global mean temperatures are rising faster with time Warmest 12 years: 1998,2005,2003,2002,2004,2006,2001,1997,1995,1999,1990,2000 150 0.0450.012 Period Rate Years /decade

Global mean temperatures are rising faster with time 100 0.0740.018 150 0.0450.012 Period Rate Years /decade

Global mean temperatures are rising faster with time 25 0.1770.052 50 0.1280.026 100 0.0740.018 150 0.0450.012 Period Rate Years /decade

Land surface temperatures are rising faster than SSTs Sea Surface T Land Annual anomalies of global average SST and land surface air temperature

Land precipitation is changing significantly over broad areas Increases Decreases Smoothed annual anomalies for precipitation (%) over land from 1900 to 2005; other regions are dominated by variability.

Proportion of heavy rainfalls: increasing in most land areas Regions of disproportionate changes in heavy (95th) and very heavy (99th) precipitation

Projected Patterns of Precipitation Change 2090-2100 Precipitation increases very likely in high latitudes Decreases likely in most subtropical land regions This continues the observed patterns in recent trends

from ocean expansion and melting glaciers Sea level is rising: from ocean expansion and melting glaciers Since 1993 Global sea level has risen 41 mm (1.6 inches) 60% from expansion as ocean temperatures rise, 40% from melting glaciers Steve Nerem

Evidence for reality of climate change Glaciers melting Muir Glacier, Alaska 1909 Toboggan Glacier Alaska 2000 1900 2003 Alpine glacier, Austria

Global mean temperatures are rising faster with time 100 0.0740.018 150 0.0450.012 Period Rate Years /decade

The impacts

Impacts on living things If the sea-levels are rising then – what might the effects be? And on people and the ecosystems? If there are more climatic hazards – what might they be? What is the impact? Where might be affected the most? Changes in rainfall – what might be the effects on the earth? On the human welfare? Rises in temperature – what would be the effects? What are the impacts on the different groups? That is the sea as well? Warming seas with more CO2 in ( that is an acid by the way)?

Impacts on living things Ecosystem changes – which would be most affected? What would be the impacts on the world as a whole? On people? On ecosystem populations? Agricultural production: all bad or maybe some good?

One of the impacts is on human health – why?

Responses to climate change

On an international level Countries get involved in UN inspired activities (more about them next term) KYOTO IPCC Copenhagen They sign up to the agreements made there – unlike the USA and Australia which did not sign up to KYOTO Individual countries make international agreements to mitigate against increased greenhouse gas emissions

Norway Offer Brazil $1 Billion to Save the Amazon by Alan Harten September 17, 2008 The prime minister of Norway, Jens Stoltenberg, has announced a donation of $1 Billion by 2015 to the International Fund for the preservation of the Amazon, created in August by Brazilian President da Silva. The Norwegian government has decided to contribute $1 Billion to the Amazon Fund, over the next few years, and payments will begin this year, explained the Norwegian prime minister. Successive contributions will depend on results in reducing Amazon deforestation. One pre-condition is that will be able to see clearly documented evidence that deforestation is actually being reduced. [Norway and the UK have also promised £50 million a-piece to the Congo for a similar project with similar rules – they are using satellite tracking to ensure their investment is well-spent]

National activities As a result of Kyoto, many MEDCs (excluding USA and Australia) have committed to reducing emission by increasing the efficiency of the use of fossil fuels in vehicles and changing the fuel source for energy generation – either by renewables and/or nuclear power, that some say must form an essential element if they are to succeed in making the cuts. They are also committed to improving the standards of house building to reduce heat loss, and paying a ‘feed-in’ tariff for smaller providers of renewable energy.

National activities Car emissions are reduced by legislation and clean electric cars get a variety of ‘good deals’. Congestion charging – started in London – is also seen as a green initiative. If a city is clogged with slow moving petrol/devisal cars stuck interminably in low gear, the emissions are much more concentrated and more damaging. Get people on the buses and the damage is far less.

Local activities Too much international trade involves boats and planes, when the goods could be produced locally. Buy locally, you support your local community and the food or goods have not travelled so far – fewer emissions! Farmers markets are gaining in popularity all over the world. Farmers are increasing getting a premium both in terms of the value of their goods that result from greener production methods and grants from the EU/government to maintain the biodiversity and reduce inputs in terms of fertilizers and pesticides.