Climate change basics

Summary

• Scientists agree climate change is a threat
• Climate change is happening and will get much worse
• Climate change is caused by people

Scientists agree climate change is a threat

There is a worldwide scientific consensus that climate change is real and dangerous.

• The National Academies of Science of the USA, UK, France, Germany, Italy, Russia, Canada, Japan, India, Brazil and China issued a statement saying ‘The threat of climate change is clear and increasing.’
• The Intergovernmental Panel on Climate Change (IPCC) won the 2007 Nobel Peace Prize for its comprehensive reports on climate change on behalf of 1,000s of scientists. It concludes: 'Warming of the climate system is unequivocal.'
• The Royal Society says: 'International scientific consensus agrees that increasing levels of man-made greenhouse gases are leading to global climate change.'
• The UK Government’s Chief Scientific Adviser, Professor Sir David King said: 'There is no bigger problem than climate change.'

Climate change is happening and will get much worse

Upsala Glacier, Argentina 1928 (above) and 2004 (below). (Photos provided by Greenpeace)

Climate change means a change in the patterns of weather that we are used to.

A few examples: The timetable of the seasons may change. Average temperatures may rise. Places that are usually frozen may thaw. Well-watered areas may have droughts, or dry places have floods. There will be more extreme weather events at unexpected times and places.

Climate is defined in terms of averages over time. Individual events cannot usually be attributed to climate change. However these are the kind of thing that are happening and we can expect more of:

• Droughts and heatwaves (30,000 died in Europe in 2003)
• Storms and floods
• Melting ice in the Arctic, Antarctic and Greenland 
• Thawing permafrost
• Retreating glaciers affects flow of rivers
• Record-breaking hurricanes (such as Katrina in 2005)
• Rising sea levels 
• Oceans becoming more acidic

Climate change is caused by people

The climate is changing because the world is warming, and that is because carbon dioxide (CO₂) is increasing in the atmosphere. CO₂ is rising because it's emitted whenever we burn oil, gas or coal (fossil fuels) to generate energy. Rich countries use a lot of energy!

Factory chimneys at winter sunset in Russia. Used with permission.

CO₂, and some other gases like methane and water vapour, act like a 'greenhouse' round the planet and keep the heat in. To a point that is good - the earth needs to be warm to sustain life. But now CO₂ is rising to super record levels. And the greenhouse effect is driving up the global temperature.

The IPCC evidence says the cause of global warming is people burning fossil fuels. Or in their words: 'Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic GHG concentrations.'

We’re the ones who’ve caused the problem and we need to do something about it.

For more info on climate change:

• Summary of IPCC Science Report 2007
• The Royal Society
• John Ray Initiative