Latest Green Research

Is the planet warming?

Yes. Every one of the hottest 15 years on record has occurred since 1980. The hottest five have been since 1997.

The world's average surface temperature increased by about 0·7°C over the 20th century. (By average we mean the average of air temperatures near land surfaces, and sea surface temperatures.) The World Meteorological Organization announced that 2005 was the hottest year on record in the northern hemisphere.

Records, which go back to 1861, show the rate of change has varied a lot. For example, most of the warming occurred during two periods, 1910 - 1945 and 1976 - 2000 (source: Intergovernmental Panel on Climate Change).

The three fastest-warming regions on the planet in the last two decades have been Alaska, Siberia and parts of the Antarctic Peninsula. Continents in the northern hemisphere have warmed the most. Computer models suggest this trend will continue.

What is 'global dimming'?

Airborne particles in the atmosphere, released since the start of the industrial revolution, mean less sunlight reaches the planet's surface. These small particles reflect the sun's heat back out to space - global dimming.

Industry and transport are reducing emissions, which is improving air quality. This could reduce the global dimming effect, and mean global warming might happen faster and be more severe.

Small airborne particles (aerosols) from natural sources, such as volcanoes, wildfires, dust, sea-salt spray and desert sands also have a cooling effect on the planet so understanding the impact of all types of aerosols on the climate is important.

Can we distinguish man-made from natural climate changes?

The overwhelming consensus among climate change scientists is that human activities, particularly those producing greenhouse gases, are responsible for much of the climate change we're seeing. The climate also changes naturally over time. This may account for some of the warming, but not all.

This consensus is apparent from work that climate researchers (including many NERC scientists) have submitted to the United Nations Intergovernmental Panel on Climate Change (IPCC). The IPCC is recognized worldwide as the definitive source of information on climate change. In 1995 the IPCC reported that the balance of evidence suggests that humans have a noticeable influence on global climate. In a further report in 2001, the IPCC concluded that most of the warming seen over the last 50 years can probably be attributed to human activities.

Computer-based climate models and actual observations from the last 140 years match most closely when the models include emissions from human activities.

The Greenhouse Effect

Some gases in our atmosphere, for example carbon dioxide, methane, nitrous oxide, and especially water vapor, trap heat emitted from the Earth's surface, keeping the planet about 30°C warmer than it would otherwise be - warm enough to support life. This is the 'natural greenhouse effect' and is scientifically well understood.

Human activities, especially burning fossil fuels like coal and oil, have increased the amount of these greenhouse gases in our atmosphere. This is throwing the climate system out of balance, causing global warming.

Carbon dioxide levels in the atmosphere have increased from about 280 ppm in the mid 18th century - the start of the industrial revolution - to around 379 ppm today. You would need to go back at least 420,000 years to find another time when carbon dioxide was at such high levels in the atmosphere.

Is the world's ice melting?

Ice sheets

Earth has two huge ice sheets: Antarctica and Greenland. Antarctica holds enough ice to raise sea levels by 70m if it melts, Greenland by 7m.

Antarctica

Climate models suggest the Antarctic ice sheet will not melt; indeed there may be some growth. Scientists predict more snowfall on the Antarctic continent making the ice sheet thicker, counteracting to some extent sea level rise caused by global warming. Even if the ice sheet grows it will not completely balance out the thermal expansion of the oceans, and the melting of glaciers outside the Antarctic region, so sea levels are still predicted to continue to rise.

NERC's British Antarctic Survey and the Centre for Polar Observation & Modelling (CPOM) are increasing knowledge of this issue.

Scientists use two methods to see whether the Antarctic ice sheet is growing or shrinking. They compare how much snow accumulates, with estimates of how much ice is lost as calving icebergs or through melting ice shelves. But this isn't very precise. Satellites can estimate how thick the ice sheet is by measuring the height of the ice surface with an altimeter. One such study showed that most of the ice sheet grows as much as it melts, but there were only a few years of satellite data and not all of the ice sheet was covered.

We may be able to predict the fate of ice sheets if we understand their past. NERC scientists at the British Antarctic Survey are investigating the 740,000 year climate record locked up in Antarctica's 4km thick ice sheet. Trapped bubbles in the ice hold an archive of atmospheric gases, and evidence for levels of global pollution by industry, agriculture and even atomic bombs. Studies on the ice sheet and its contribution to world sea level rise are vital in helping us understand global change.

For more information, follow the links above right.

Greenland

The Arctic is one of the fastest warming regions on the planet. Climate models indicate that the local warming over Greenland is likely to be one to three times the global average. Ice sheet models project that a local warming of larger than 3°C, if sustained for thousands of years, would lead to virtually a complete melting of the Greenland ice sheet, with a resulting sea level rise of about 7m. A local warming of 5·5°C, if sustained for one thousand years, would be likely to result in a contribution from Greenland of about 3m to sea level rise.

Sea ice

Arctic sea ice is melting. Scientists monitored record losses in August and September 2005. September is the month when sea ice reaches its minimum. Satellite data suggests the Arctic has lost 20% of its September sea ice since 1978. Climate models predict that as early as the year 2070 there will be no sea ice in the Arctic during the summer months.

Melting sea ice does not directly affect sea levels, as the ice is already afloat. But the melting will affect climate indirectly by changing ocean circulation patterns and reducing the amount of the sun's heat reflected back out to space - accelerating global warming. Sea ice loss is already becoming a problem for some animals, such as polar bears.

Glaciers

The world's glaciers are receding. The melting is making a significant contribution to global sea level rise (thermal expansion of the oceans is the cause of most of the sea level rise). The World Glacier Monitoring Service in Switzerland surveyed 88 glaciers in 2002 and 2003. They found 79 were melting and only four were growing.

In the short term this could cause more flooding, in the long term it could add to the drought problems in some areas as rivers dry up.

Balsa tree platform for green surfboard

Creators of a new environmentally friendly surfboard believe it could revolutionise the industry.

The Eco board, produced by British company The Eden Project, was launched last week in England. More than half of the materials used in its construction were renewable.

The prototype board was made with timber from a fallen balsa tree which toppled in the Eden Project's ecological tourist park in 2003.

In deciding how best to use the timber, creators Chris Hunes and Pat Hudson and three Cornwall companies made a surfboard core, with more environmentally friendly materials than those used in conventional board production.

Retail director, Mark Beeley, said the surfboard had been tested for performance by professionals. Its starting price was $945. Junior British surfing champion Tassy Swallow said: "It will really catch on when people realise it is just as good as a regular board."

Article from the Herald