The problem with climate change and the global rise in temperatures is that it changes and disrupts the way that the planet works. There is no one single impact – it depends where you are on the planet as to what the direct effects of a changing climate will mean for you. But around the world we are seeing some very worrying impacts which will lead to billions of people suffering and possibly many millions of people dying because of climate change.

On top of this some of the world's most treasured natural jewels – our wildlife and wild places – may be destroyed forever, some examples of which can be found in the UK. It may be that cod, which is at its southern limit in the UK and is already heavily depleted from over fishing, may move north and be lost from UK waters altogether.

While the results of climate change on the UK look set to be less dramatic (though still serious) in the short term, the impacts on the rest of the world will have an enormous knock-on effect here too. More

For example, coral reefs which provide the homes for many fish species may be largely lost by 2030. Fifty million people from around the world rely on fish from coral reefs as their main source of food.







One example of the worrying impacts of climate change is the rapid melting of glaciers in the Himalayas – the huge mountain chain that runs through the middle of Asia.

The Himalayan glaciers are giant rivers of ice that contain the largest store of fresh water outside the poles, and feed seven great Asian rivers including the Yangtze, Yellow River, Ganges, Mekong and Indus. More than a billion people rely on these glaciers to provide water for drinking, sanitation, agriculture and even power generation from hydroelectric plants.

The rapid melting of Himalayan glaciers is set to have two devastating impacts:

• Firstly, to increase the volume of water in rivers, causing widespread flooding. Then, in a few decades the water level in rivers is set to seriously decline, leading to massive humanitarian, social and environmental problems for people in western China, Nepal and northern India – as less fresh water means less agriculture, less food and less income.
• Secondly, These regions are also where some of the world's most spectacular biodiversity can be found – many of the world's tigers, rhino and elephants, for example, depend on this water supply to survive. More

Corals
When the atmosphere warms up, so do the world's seas - causing many dramatic problems.

One obvious problem is that warming seas are having a terrible impact on the world's coral reefs. These reefs are effectively the rainforests of the seas, with a staggering array of different types of fish and other marine animals living in and around them.

But coral is a living organism, and it is extremely sensitive to changes in temperature. As the world's oceans increase in temperature, the coral reefs are bleaching and dying. It is estimated that if the global rise in temperature is not stopped there will be just 5% of Australia's Great Barrier Reef - the world's largest coral reef - left by 2050.

But this is not just an environmental tragedy as coral reefs provide enormous quantities of food for humanity. Around half a billion people - a twelfth of the entire population of the world - relies on fish from coral reefs as their main source of protein. If the reefs are destroyed, so is this wonderful larder for the planet. More


Climate change is also increasing the severity and frequency of extreme weather events like hurricanes, which damage corals further, and man-made CO₂ is also now starting to mix with seawater to form carbonic acid, which increases the acidity of the sea and prevents corals from being able to create their calcium shells. On top of this, extreme weather events often have tragic implications for people. Hurricane Katrina, which recently devastated New Orleans, is a case in point. The massive cost of dealing with this sort of incident repeatedly also adds to the economic imperative for tackling climate change.


At least a third of all man-made carbon emissions are absorbed by the world's seas. This removes CO₂ from the atmosphere and therefore reduces its impact on global warming.

The carbon is absorbed in two ways:

1. Firstly – and most importantly – by microscopic plants called phytoplankton which separates the carbon from the oxygen, and releases the oxygen back into the atmosphere – in fact about half of the world's oxygen comes from phytoplankton. These plants are then eaten by microscopic animals – called zooplankton – which absorb the carbon from the plants into their shells and bodies. When these animals die they sink to the bottom of the oceans and take the carbon with them, effectively locking it away and ending its ability to contribute to global warming.
2. The other, more worrying, way that the carbon is absorbed by the seas is where it dissolves into seawater and forms carbonic acid. This is increasing the acidity of the seas, and threatens many marine creatures like coral and some plankton.

However, the ability of the seas to continue absorbing huge quantities of man-made carbon emissions appears to be reaching its limit as seas warm, ocean currents change and plankton productivity reduces.


One of the most obvious signs of a changing climate is the rapid loss of summer sea ice in the arctic – this is the sea ice that is left when the temperatures rise during the natural summer temperature increase.

Average temperatures in the Arctic are increasing at twice the global average. It is predicted that by 2090 some areas of the Arctic will see air temperatures increase by 12 degrees Celsius, and the Central Arctic Ocean winter temperatures may increase by 8-9 degrees Celsius.

It is estimated that since the 1970s, 14% of perennial sea ice has been lost from the arctic and that over the past century temperatures in the arctic have risen by about 5 degrees centigrade. Some scientists estimate that by 2040 there will be little sea ice left at the poles at all in the summer.

There are obvious problems related to this for arctic wildlife. Polar bears depend on the sea ice to reach their hunting grounds, and without it they face starvation. Many species of whale depend on the Arctic as their main feeding ground. Currently the Arctic ocean is the most productive marine ecosystem in the world and home to the highest density of birds in the world. Loss of sea ice and rising temperatures will reduce food availability for whales, seals, polar bears and sea birds. See WWF's recent fact sheet on the impacts of climate change on the Arctic.