Global warming 'threat to nature's variety'

A third of all flora and fauna will become extinct if global warming continues unchecked, researchers warn.

Scientists say that the impact of climate change has been underestimated, and while species as a whole will survive, variations within them will die out.

The team, from the Biodiversity and Climate Research Centre in Frankfurt, says that by 2080 more than 80 per cent of genetic diversity within certain species will disappear.

Most models on the effects of climate change on flora and fauna focus on species as a whole, but diversity within a species has not been taken into account.

Dr Carsten Nowak investigated nine aquatic insect species in streams around central and northern Europe. If climate change progresses as predicted, they will be pushed back to a few small areas in Scandinavia and the Alps, a computer model suggests.

A rise of two degrees would see at least one species wiped out, and a rise of four degrees at least two. But because of the extinction of local populations, genetic diversity would be much more adversely affected, with as many as 84 per cent of genetic variants dying out by 2080.

Global Warming - Fast Facts

• At the rate our climate is changing, the world will soon be warmer than at any time in th last 10,000 years.
  
• The world has warmed by 0.5 degC over the past century and an average 2 degC warming is predicted by 2100.
  
• There is scientific consensus that air pollution from human activities is partly responsible for global warming.
  
• Climatic changes will alter natural vegetation, wildlife habitats, crop growing seasons, and distribution of pests and diseases.
  
• Global warming will cause a continued and accelerated rise in sea levels, threatening half of the world's most critical coastal wetlands.
  
• A one-meter rise in sea level would threaten half of the world's coastal wetlands of international importance for their biodiversity.
  
• A 3 degC to 4 degC warming could eliminate up to 85% of the remaining wetlands in the semi-arid regions of southern Europe.
  
• The loss of wetlands in the flood plains of rivers in the African Sahel could make some local populations of turtles and birds extinct.
  
• A 3 degC to 4 degC warming could eliminate all open waters of the prairie pothole region in the US, an area where half of the wild duck population hatch out.
  
• About 30 new infectious diseases have emerged in the past 20 years.
  
• Global warming will expose millions of people to new health risks. Infectious diseases are emerging, resurging and undergoing redistribution on a global scale.
  
• Global sea level has risen between 10 to 25 cm in the last 100 years and will rise faster still in the coming decades.
  
• By the year 2050, up to one million additional deaths from malaria may be occurring annually as a result of climate change.
  
• The arctic is unusually important for migratory birds. An estimated 15% of the world's bird species are arctic specialists. In north america, 36 species breed only above 60 degN latitude.
  
• Ringed seals are the principal prey of polar bears. Unseasonal warming can lead to collapses of the snow caves where female seals bear their young. The young as yet have no blubber and die of exposure when cold conditions return. Scientists suspect that declines in seal populations will occur in this manner, and will ultimately lead to declines in polar bear populations.
  
• Detailed climate models suggest that a doubling of greenhouse gas concentrations will lead to a 30% reduction in the tundra available to Arctic species.
  
• Many of the world's most distinctive mammals are found only in the Arctic, including walrus, several species of seals, arctic foxes, collared lemmings, arctic and tundra hares, muskoxen, polar bears, mmarwhals and bowhead whales.
  
• As sea ice becomes thinner due to increased temperatures, animal intruders from the south, such as grizzly bears and moose, are penetrating north affecting local populations.
  
• Between 15 to 20% of the large nature reserves in southern reserves in southern Africa would experience a change in biome or habitat type under different climate change scenarios.
  
• Climatic changes will alter natural vegetation, wildlife habitats, crop growing seasons, and the distribution of pests and diseases.

Global Warming - Science

GLOBAL Warming factors

G Gases

L Light

O Orbit

B Balance

A Acceleration

L Land use

The combinations of these factors is producing climate change. No one knows the relative importance of each. Each has been very significant in the past or could be in the future. Only some of these factors are affected by human activity.

G – Gases

We are changing the content of every breath we take. Several different gases are poisoning life on earth – and not just carbon dioxide.

Each gas is important, produced in different ways, but with twenty-fold differences in their effects per ton. But we need more data on the human use of carbon, as a proportion of total global emissions. These gases don’t just come from human action. Volcanoes for example have a significant effect.

Evidence from ice cores allows us a crude review of earth history. Trapped in deep layers of ancient ice several kilometres thick are tiny bubbles of air. These layers can be read like rings on an ancient tree – one per year – taking us back a million years. And in each bubble is a perfectly preserved mix of gases which is identical to what it was in that year.

The ice too tells us a story: different forms of hydrogen atoms (isotopes) are more common at different atmospheric temperatures, and these too are locked into ice layers. So we can build up a picture year by year not only of carbon dioxide levels, but also an indication of earth temperature.

Scientists have noted that in many cases the temperature seems to rise BEFORE carbon dioxide levels. Maybe another event triggers the process, and then it becomes self-perpetuating for a while as increased carbon dioxide leads to more warming and more carbon dioxide and so on.

Water vapour is also significant – especially when millions of tons are pumped into the upper atmosphere by aircraft, producing vapour trails that contribute up to 15% of cloud cover in some parts of the world. Many scientists think that more trails means more insulation, and warmer temperatures.

L – Light

Life on earth depends on heat from the sun, but this is powered by a massive nuclear fusion reaction, which varies in power. Over past millions of years, these natural shifts have affected climate. That’s why scientists are so interested in solar flares and spots.

O – Orbit

The earth is tilted on an axis, so that as we journey around the sun the seasons change. Because the earth is mostly a red hot core of molten rock, the mass of the earth shifts as it turns, creating a slight wobble, or change in axis over millions of years. In the past such small changes may have had a huge effect by increasing or decreasing seasonal variations.

B – Balance

The earth has powerful self-regulatory mechanisms. We don’t know the limit of self-regulation. It is impossible to calculate the risks of major disruption by our own actions.

Over millennia the natural balance has shifted. Vast amounts of atmospheric carbon has been captured by plants and trees. A significant amount has been gradually stored away over millions of years in oil, gas, coal and peat deposits – hugely undone in just a hundred years of burning.

A – Acceleration

Our world contains a number of feedback loops which are huge risks for our future. We could see an accelerating process, a spiral of disaster. Take peat: wet peat is stable but as it dries in warmer weather, it becomes food for fungi and bacteria and is rapidly decomposed into carbon dioxide. Peat decomposition could be a significant source of carbon dioxide emissions in future.

L – Land use

While clearing of forests has obvious impact, so does how land is cultivated (variations in radiant energy and evaporation) or used for animals (methane production from sheep or cattle is xx% of total global emissions.)

Then there is biofuel. It’s easy to make diesel from food, but making food also uses energy in machines, fertiliser and transport. Net energy gain may be small. Using biowaste sounds more ecowise but robs soil of natural fertiliser, so synthetic fertiliser is needed which also uses energy. Biofuel use has pushed up food prices dramatically which is causing hardship to the poorest around the world. They cannot compete with wealthy car owners who want to fill their vehicle tanks with food.

A paradox: while the surface of the earth is warming, the inside core is cooling. If the earth were the size of a football, the earth’s crust would be the thickness of little more than an egg shell. The rest is red hot liquid stone, and as we will see, this offers huge opportunities for energy generation.