Methane plumes reveal vicious climate circle
Scientists have discovered that, as global warming melts arctic ice, methane is being released from the sea. Does this ‘positive feedback loop’ mean climate change could become irreversible?
Flying over the Arctic Ocean, a team of scientists looked out at an awe-inspiring scene. Thousands of feet below, glistening sea-ice stretched out for miles. Both the scientists on board and their high-tech computers – made to detect tiny chemical changes in the air – were quiet.
Then, the plane passed over a crack, where the ice had melted and fractured. The system leapt into life: above the black ocean, the concentration of methane molecules in the atmosphere was extraordinarily high. A plume of the gas, it seemed, was rising from the watery depths.
The team had made a worrying discovery. That the freezing seas of the north are rich in methane was something they had known for years. The surprise lay in the fact that the gas was escaping – as global climate change warmed and melted the thick arctic ice.
For those worried about rising temperatures, the release of methane is seriously bad news. When it comes to trapping heat in the atmosphere and warming the planet, the gas is twenty times more potent than carbon dioxide. And though scientists are unsure about how significant the effect of that might be, it could be a hint of what is to come in our changing climate.
That is because the discovery is yet another example of ‘positive feedback’ – when the effects of an event or phenomenon cause it to happen again, with greater intensity. When it comes to climate change, that means that as the Earth gets hotter, the pace of warming speeds up even more. Climate change could be a vicious circle.
One example of this concerns melting ice. Today, the vast ice caps that cover much of the planet cool the globe by reflecting the sun’s rays. As temperatures rise, however, this ice melts – revealing dark land or ocean that absorbs more heat. That means the globe gets even hotter, melting even more ice and forcing temperatures up and up.
This loop of positive feedback is a huge worry for many scientists. Some even fear the vicious circle could bring the planet to a ‘tipping point’ – when global warming becomes uncontrollable. Then, they fear, even stopping the release of carbon and methane emissions will have no effect – and the planet will continue to grow hotter of its own accord.
In hot water?
When faced with this sobering scenario, many give up hope that we can ever put an end to global warming. Much better, they say, to accept that the planet is getting hotter – and use the power of technology to protect against the consequences.
Others think it is foolish to lose hope when there is still time to take action. Global warming, they say, might be getting worse – but that should just motivate us to act now, and quickly. It may be a challenge, but we can still halt the warming of our world.
- Is it hopeless to try and prevent climate change?
- In a time of global recession, should governments make climate change a top priority?
- Think of five steps that you can take, as a school, to reduce carbon emissions and tackle global warming.
- In small groups, discuss examples of vicious circles, in the world of climate change, or daily life. Choose one, and display it using a graphic, like the one above. Think of one intervention that could stop the circle continuing.
Some People Say...
“There’s nothing we can do to stop global warming.”
What do you think?
Q & A
- So how bad are things really?
- Problematically, no one is entirely sure about what climate change will mean for our planet. According to one study, we have 56 months to act – after that time, there will be so much CO2 in the atmosphere that preventing irreversible climate change will be difficult.
- And what will that mean?
- Again, there’s a great deal of doubt about what it will mean. But if the tipping point is reached, it is thought that weather systems will become more volatile. That means changed systems of wind, rain and ocean flow – and not always in the ways you might expect. Some research, for example, suggests the Gulf Stream – a flow of warm water in the Atlantic ocean – could be altered, leading to a cooler climate in North America and the UK.
- Carbon dioxide
- Carbon dioxide occurs naturally in our atmosphere. Recently, however, the concentration of CO2 in our atmosphere has increased – from 280 to 380 parts per million since pre-industrial periods. That is thought to contribute to a ‘greenhouse effect’, trapping heat in the earth’s atmosphere and heating the planet.
- Vast ice caps
- Although scientists agree some of the ice that covers vast swathes of Greenland and the Arctic is melting, estimates vary about exactly how much has disappeared. In a recent study, scientists estimated that, between 2003 and 2010, Earth’s glaciers, ice caps and mountains lost a total of 1,000 cubic miles of ice – adding about 12 millimetres to global sea levels.
- Vicious circle
- A vicious circle is a colloquial term for an activity that reinforces itself through positive feedback – such as the phenomenon of melting ice that causes further warming. A vicious circle refers to negative behaviour being reinforced; a more positive process might be described as a virtuous circle.