What is global warming?
Global warming is the rise in temperature of the earth's atmosphere.
It's said that by the time a baby born today is 80 years old, the world will be 6 and a half degrees warmer than it is now.
Is global warming bad?
The earth is naturally warmed by rays (or radiation) from the sun which pass through the earth's atmosphere and are reflected back out to space again.
The atmosphere's made up of layers of gases, some of which are called 'greenhouse gases'. They're mostly natural and make up a kind of thermal blanket over the earth.
This lets some of the rays back out of the atmosphere, keeping the earth at the right temperature for animals, plants and humans to survive (60°F/16°C).
So some global warming is good. But if extra greenhouse gases are made, the thermal blanket gets thicker and too much heat is kept in the earth's atmosphere. That's when global warning's bad.
What are the greenhouse gases?
Greenhouse gases are made out of:
They are all natural gases, but extra greenhouses gases can be made by humans from pollution.
How are extra greenhouse gases produced?
Extra greenhouse gases are produced through activities which release carbon dioxide, methane, nitrous oxide and ozone CFCs (chlorofluorocarbons). These activities include:
Burning coal and petrol, known as 'fossil fuels'
Cutting down of rainforests and other forests
Animal waste which lets off methane
What's the 'ozone layer' got to do with global warming?
The ozone layer is another important part of the atmosphere.
It's made up of ozone (a type of oxygen) that protects the earth from too many harmful rays called USB.
So what could happen?
If Earth gets hotter, some of the important changes could happen:
Water expands when it's heated and oceans absorb more heat than land, so sea levels would rise.
Sea levels would also rise due to the melting of the glaciers and sea ice.
Cities on coasts would flood.
Places that usually get lots of rain and snowfall might get hotter and drier.
Lakes and rivers could dry up.
There would be more droughts making hard to grow crops.
Less water would be available for drinking, showers and swimming pools.
Some plants and animals might become extinct because of the heat.
Hurricanes, tornadoes and other storms which are caused by changes in heat and water evaporation may get more common.
What's being done about it?
The United Nations has meetings where world leaders agree on what to do about global warming.
Every five years, the Earth Summit happens.
In 1997 there was an Earth Summit in Rio de Janeiro and in 1997, an agreement was made at the UN Conference on Climate Change in Kyoto, Japan, to cut the amount of gases that industries make.
Leaders agree the world can cut the amount of carbon dioxide that's released into the atmosphere by changing the way power is produced too.
In February 2003, the British Government set out its plans to produce electricity using "greener" ways.
What can I do?
There are ways you can help cut greenhouse gases and help stop global warming.
They are simple things, but can make a difference if everyone does them!
Re-cycle glass bottles, jars, newspapers and magazines and tin cans. Save them and take them to local re-cycling centres.
Re-use plastic shopping bags and envelopes, don't get new ones
Persuade you mum or dad (or whoever does the gardening) to have a compost heap.
Put a brick in a plastic bag into your toilet cistern, then the toilet will use less water each time you flush. Don't worry that's plenty of water to get rid of...
Use paper on both sides. Try and buy products that don't use much packaging.
Give unwanted gifts and clothes to a charity shop.
Only fill the kettle up with the amount of water you need to boil that time.
Don't leave the TV or video on standby.
If you get lift to school in a car, take your mates along for the ride.
Ask whoever does your washing to use the machine at 40 degrees, this helps conserve power.
Switch lights off when you're not in the room
Get a clockwork mobile phone recharger
Cycle to places!
Have showers instead of baths.
Global warming is depleting our water supply:
Hong Kong - Finding ways of combating worldwide water shortages caused by global warming is one of the questions expected to top the agenda at the third World Water Forum which gets underway on Sunday.
Record droughts have parched crops, decimated flocks and turned once-picturesque landscapes to desolate brown as scientists warn that climate change will strain already limited fresh water supplies.
"Water supplies are falling while the demand is dramatically growing at an unsustainable rate," the United Nations said in a report released to mark the International Year of Freshwater, ahead of Sunday's conference in Kyoto, Japan.
"The future of many parts of the world looks bleak."
Global warming will in the future be responsible for one-fifth of global water scarcity because of its impacts on rainfall patterns, with more frequent and longer-lasting droughts baking wider expanses of land, the UN said in its report.
A 2001 report by the Intergovernmental Panel On Climate Change (IPCC) found that the average surface temperature of the Earth has increased by 0.6°C over the course of the 20th century, which has led to a decrease in snow and glacier cover.
And while precipitation has increased by half a percent per decade over most of the middle and high latitude regions of the Northern Hemisphere, increases in rainfall in tropical countries are not evident.
"Over the 20th century there were relatively medium increases in global land areas experiencing severe drought or severe wetness," the IPCC wrote.
"In some regions, such as parts of Asia and Africa, the frequency and intensity of droughts have been observed to increase in recent decades."
Such droughts have compounded the already dire circumstances for millions, many of whom live in arid climates and under impoverished conditions that limit their access to fresh water.
A dry rainy season in eastern Ethiopia, for example, has threatened the lives of more than one million people - many of them children - as there is no way to irrigate even subsistence crops.
Efforts to rebuild the central Asian nation of Afghanistan after 23 years of war have also been made more difficult by drought, with the water table in the capital, Kabul, dwindling at a rate of one meter every year.
The UN has set itself a goal of reducing by one billion the number of people with limited access to fresh water by 2015, and ways of achieving that target will be discussed at the Kyoto forum. - Sapa-AFP.
The scientific community has reached a strong consensus regarding the science of global climate change. The world is undoubtedly warming. This warming is largely the result of emissions of carbon dioxide and other greenhouse gases from human activities including industrial processes, fossil fuel combustion, and changes in land use, such as deforestation. Continuation of historical trends of greenhouse gas emissions will result in additional warming over the 21st century, with current projections of a global increase of 2.5ºF to 10.4ºF by 2100, with warming in the U.S. expected to be even higher. This warming will have real consequences for the United States and the world, for with that warming will also come additional sea-level rise that will gradually inundate coastal areas, changes in precipitation patterns, increased risk of droughts and floods, threats to biodiversity, and a number of potential challenges for public health.
Addressing climate change is no simple task. To protect ourselves, our economy, and our land from the adverse effects of climate change, we must ultimately dramatically reduce emissions of carbon dioxide and other greenhouse gases. To achieve this goal we must fundamentally transform the way we power our global economy, shifting away from a century’s legacy of unrestrained fossil fuel use and its associated emissions in pursuit of more efficient and renewable sources of energy. Such a transformation will require society to engage in a concerted effort, over the near and long-term, to seek out opportunities and design actions to reduce greenhouse gas emissions.
Global warming poses an extraordinary challenge. The world's leading atmospheric scientists tell us that a gradual warming of our climate is underway and will continue. This long-term warming trend poses serious risks to our economy and our environment. It poses even greater risks to many other nations, particularly poorer countries that will be far less able to cope with a changing climate and low-lying countries where sea level rise will cause significant damage.
Meeting the challenge of global warming will require sustained effort over decades - on the part of governments, who must establish the rules and modify them as we learn more of the science, and as technological solutions begin to manifest themselves; on the part of industry, who must innovate, manufacture, and operate under a new paradigm where climate change will drive many decisions; and on the part of the public, who must also switch to a more climate-friendly path in their purchases and lifestyles.
What's Being Done About Global Warming
The issue of global warming is one of the most profound challenges of our time, and we believe it is a challenge that can be met. But responding effectively will not be easy, because the causes and consequences of global warming—as well as the solutions to this problem—cut across every nation, every sector of the economy, and every community.