How bad global warming gets depends mostly on how far we humans let greenhouse gases continue to spiral upwards – and that’s where this website comes in. The Intergovernmental Panel on Climate Change, the main scientific body on this issue, states that termperatures will increase by 1.4 degrees celcius to 5.8 degrees over the next hundred years.
The key uncertainty here is not hw the atmosphere will behave, but how humans will behave. Will seven or more billion humans continue to seek fossil fuel-hungry lifestyles with cars and planes and such? Or will we develop cleaner energy sources and treat amore lightly on the planet? There’s no clear answer, the ultimate answer will depend on decisions made by each and every one of us.
Here’s what will happen when the earth temperature rises just one degree at a time.
One Degree:-
- Deserts invade the High Plains of the USA in a much worse repeat of the 1930’s dustbowl. While the epicentre is Nebraska, states from Ontario in the north to Texas in the south will suffer severe agricultural losses.
- Mount Kilimanjaro loses all it’s ice.
- The Gulf Stream switches off – perhaps plunging Britain and Europe into icy winter cold.
- Rare species, like forest-dwelling frogs, possums and tree kangaroos, are wiped out in the Queensland rainforest, Australia, as warming erodes their habitat.
- Coral Reefs around the world suffer increasing losses from bleaching and are wiped out, with the Great Barrier Reef largely destroyed by 2030.
- Island nations submerge under the rising seas.
Two Degrees:-
- Oceans turn increasingly acidic, further hitting coral reefs and endangering the marine ecosystem.
- One summer in two has heatwaves as strong as 2003’s disaster in Europe.
- Greenlands tips into irreversible melt, accelerting sea level rise and threatening coastal cities around the world.
- Polar bears, walruses and other ice-dependent marine mammals become extinct in the Artic as the icecaps disappear.
- Drought, fire and searing heat strike the Mediterranean basin.
- Declining snowfields threaten water supplies in California.
- A third of species worldwide face extinction as the climate changes.
Three Degrees:-
- The Kalahari Desert spreads across Botswana, engulf the capital in sand dunes, driving millions of refugees out to surrounding countries.
- A permanent el nino grips the Pacific causing weather chaos around the world and drought in the Amazon.
- Water runs short in Perth, Sydney and other parts of Australia away from the far north and sounth.
- Agriculture shifts into the far north – Norways growing season becomes like southern England is today. But with declines in the tropics and sub-tropics due to the heat and drought, the world tips into net food deficit.
- The whole Amazonian ecosystem collapses in a conflagration of fire and destruction. Desert and savannah eventually take over where the world’s largest rainforest once stood. Huge amount of carbon pour into the atmosphere, adding another degree to global warming.
- Hurricanes strike the tropics that are half a category stronger than today’s, with higher wind speeds and rainfall. Wind speeds in the strongerst storms could rise to 200 miles per hour.
- The Indus River runds dry due to glacial retreat in the Himalayas, forcing millions of refugees to flee Pakistan. Possible nuclear conflict with India over water supplies.
Four Degrees:- (Are we getting the message yet?)
- Most of the Nile Delta is threatened by rising seas, as is a third of Bangladesh. Tens of millions more become climate refugees.
- West Antartic ice sheet potentially collapses, pumping five metres of water into global sea levels
- Southern Europe becomes like the Sahara, with deserts spreading in Spain and Portugal.
- All glaciers disappear from the Alps, further reducing water supplies in Central Europe.
- Permafrost melt in Siberia releases billions of tonnes of methane and carbon dioxide, meaning even larger increases in global warming.
Five Degrees:-
- Earth is hotter than it has been in over 55 million years.
- Desert belts expand from the subtropics into termperate regions. Civilization collapses as humanity is unable to cope.
- Methane hydrate is realeased from underneath the oceans, sparking tsunamis in coastal regions and pushing global warming into an unstoppable spiral.
- Much of the world in uninhabitable.
Six Degrees:-
- Mass extinction scenario:- The end permian mass extinction 251 million years ago was associated with six degrees of warming, and wiped out 90% of life on earth. No one is sure what happenened, but a combination of volcanic CO2, releases and methane hydrates may have been the cause ( This was much worse than the end-cretaceious mass extinction, 65 million years ago, which wiped out the dinosaurs).
- Huge firestorms sweep the planet as methane hydrate fireballs ignite.
- Seas turn anoxic (without oxygen) and release poisonous hydrogen sulphide
- Humanity’s very survival as a species is in question?
(This is an brief, extract summery from the book called Six Degrees, written by Mark Lynas, published in March 2007 by Fourth Estate)
