03 April 2012

Scientists Warn Climate Change May Be Irreversible

by Julie Rodriguez
Scientists at the Planet Under Pressure conference have some bad news for the environmental movement. Anyone paying attention could tell you that global warming is out of control. Temperatures are already set to rise by at least 2 degrees Celsius in the next century – and there may be nothing we can do to change it at this point.

But if we continue to pollute the Earth without taking drastic measures to change our emissions, the global temperature could rise by as much as six degrees. It may not seem like a huge difference, but it’s significant enough to profoundly alter the Earth as we know it. Sea levels will rise. The polar ice sheets will disappear. Rainforests will die. There won’t be any coming back from these changes.

These shifts in the climate of the Earth represent tipping points – and some scientists say that the tipping point for the melting ice sheets has already passed. There may be no way to recover them. In low-lying countries like Tuvalu or Kiribati, citizens are already making plans to evacuate as rising sea levels gradually swallow up their island homes.

But if the Amazon rainforest reaches a tipping point caused by higher temperatures and a drier climate, it could be devastating. The dying trees would stop absorbing emissions and instead release even more carbon into the atmosphere.

And nobody knows what will happen if the permafrost begins to melt in Siberia. The frozen soil stores billions of tons of carbon – twice as much as the atmosphere now. Severe temperature changes could unlock all that carbon, intensifying climate change dramatically. In an interview with Reuters, Will Steffen, the executive director of the Australian National University’s climate change institute, explained:

“There is about 1,600 billion tonnes of carbon there – about twice the amount in the atmosphere today – and the northern high latitudes are experiencing the most severe temperature change of any part of the planet,” he said.

In a worst case scenario, 30 to 63 billion tonnes of carbon a year could be released by 2040, rising to 232 to 380 billion tonnes by 2100. This compares to around 10 billion tonnes of CO2 released by fossil fuel use each year.

These changes in the atmosphere also make the oceans more acidic, as the water absorbs more carbon. We’re already witnessing an increase in ocean acidity. This change in the ocean threatens coral reefs could quickly lead to the extinction of many marine species within the next few decades.

Bob Watson, the former head of the UN’s climate panel and current chief advisor to Britian’s environment ministry, is not optimistic. Given current worldwide commitments to combatting climate change, he believes it’s entirely likely that global temperatures will rise by 5 degrees Celsius (9 Fahrenheit) by the end of the century:

“If you look at the commitments today from governments around the world, we’ve only got a 50-50 shot at a 3 C (5.4 F) world, almost no chance of a 2 C (3.6 F) world, and to be quite honest I would say it’s not unlikely that we will hit a 5 C (9.0 F) world,” said Watson.

“That is clearly a world with significant adverse consequences for ecological systems, for socio-economic systems and for human health.”

He added: “We have to realise that we are looking at a loss of biodiversity that is unprecedented in the last 65 million years… We are clearly entering the (planet’s) sixth mass extinction.”

It’s important to note that despite these dire predictions, not all scientists are completely pessimistic. Steffan told an audience in London on Tuesday, “This is the critical decade.” While the implications are terrifying – if we don’t reduce global greenhouse gas emissions significantly in the next decade, the results could be catastrophic – there’s also the possibility that things can be turned around, or the damage at least limited. But we have to act quickly.

The good news is that we have at least the next ten years before the worst of global climate change becomes completely irreversible. If we plan for the worst, that’s a full decade to lobby our lawmakers and insist upon change. As more severe weather begins to occur as a result of climate change, maybe more US lawmakers will start being willing to concede it exists and take action to stop it. (Well, we can hope, can’t we?)

350.org is placing their efforts on that hope this year – for their global day of action on May 5, they’re urging protestors to “connect the dots” between carbon emissions, global warming, and extreme weather. You can find out more about the event and how you can participate on their website, ClimateDots.org.

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