The ocean currents that bring warm water from the tropics up to the North Atlantic are being slowed down by climate change.
The consequences of the collapse of the Atlantic conveyor are looked at in our research.
The collapse of this system would cause the Earth's climate to change into a La Nia-like state.
It would mean more flooding rains over eastern Australia.
East-coast Australians are used to the La Nia weather pattern. Two summers of La Nia helped warm the ocean north of Australia.
The record-breaking floods in New South Wales andQueensland were caused by both.
Over the southwest of North America, there have been a record number of fires, with the cost of the fires alone estimated to be at least 70 billion dollars.
The climate on Earth is constantly changing. Our current trajectory of greenhouse gas emissions is giving the whole system a giant kick that will have uncertain consequences, which will rewrite our textbook description of the planet's ocean circulation.
The warm tropical water in the North Atlantic helps keep the European climate mild while allowing the tropics to lose heat. In the Southern Hemisphere, there is an equivalent overturn of the waters ofAntarctica.
Climate records show that the Atlantic overturning circulation has stopped or slowed during ice ages.
When the Earth's climate is warmer, it switches on and appeases European climate.
The Atlantic overturn has been stable since the beginning of human civilization. Scientists are worried about a slowdown that has been detected over the last few decades.
Why is it taking so long? Global warming has caused the melting of polar ice caps.
When the ice caps melt, they dump a lot of freshwater into the ocean, making it more hospitable.
In the past two decades, 5 trillion tons of ice has melted around the world. That's the amount of water in the Harbours.
If global warming continues, the melt rate is going to increase.
The world's oceans would be altered by a collapse of the North Atlantic.
It would deplete the oxygen in the air and starve the upper ocean of the upwelling of food and water. The implications for the marine environment would be significant.
The Atlantic overturning is at its weakest for at least the last millennium with predictions of a collapse in coming centuries if greenhouse gas emissions go unaddressed.
We used a global model to look at the climate under such a collapse.
We applied a massive meltwater anomaly to the North Atlantic and compared this to an equivalent run with no meltwater applied.
We wanted to look beyond the well-known regional impacts around Europe and North America and to check how Earth's climate would change in remote locations.
A huge pile up of heat builds up just south of the Equator if the Atlantic doesn't overturn.
The warm moist air is pushed into the upper troposphere by the excess of tropical Atlantic heat.
Warm water is pushed towards the Indonesian seas by the trade winds. This will help put the Pacific into a La Nia-like state.
La Nia summers are cool and wet in Australia. Flooding rain is one of the worst impacts of climate change.
The shutdown of the Atlantic would be felt as far south as the South Pole. Warming air over the West Pacific would cause changes in the wind. The low-pressure system over the Amundsen Sea is deepened by this.
As far west as the Ross Sea, this low-pressure system is believed to influence ice sheet and ice shelf melt.
Our climate system has never been affected by changes in atmospheric gas composition like what we are imposing today by our burning of fossil fuels.
The ocean slows the pace of change by absorbing heat and carbon in large quantities. With sea level rise, ice melt, and a slowing of the Atlantic overturning circulation projected for this century, there is payback.
The North Atlantic region will not be the only one affected by this slowdown.
We can grow a new low-carbon economy. For the second time in less than a century, the course of Earth's climate history will change as a result of doing so.
Matthew England is a professor at the University of New South Wales and the deputy director of the Australian Centre for excellence inAntarctic Science.
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