The shocking price of using up fossil fuels
Emissions would stay in the atmosphere for more than 5,000 years, scientist says
Margaret Munro, CanWest News Service
http://www.canada.com/vancouversun/news/story.html?id=e605ed94-9c7f-42fa...
Published: Thursday, May 31, 2007
Burning all known reserves of fossil fuels, from Alberta's tarsands to China's vast stores of coal, would have much graver long-term consequences than previously thought, according to climate scientists.
"Not only are we going to mess up our kids' and grandkids' lives, we are going to be interfering with the way the planet works for thousands of years," says climate scientist Alvaro Montenegro, noting that much of the carbon emissions would persist in the atmosphere more than 5,000 years and drive up global temperatures for millennia.
Using sophisticated computer models, Montenegro and colleagues at the University of Victoria and the University of Chicago assessed the impact of consuming all known reserves of fossil fuels until they run out in 2300. Their simulations assume that the carbon dioxide producing by burning the fuel would waft into the atmosphere as it does today.
"If we keep doing what we're doing right now, and the only thing that [stops] us from burning fossil fuels is the end of fossil fuels, that's what the experiment represents," says Montenegro, who presented the findings at an international meteorological conference in Newfoundland and Labrador on Wednesday. The study is to be published later this year.
Asking what might happen if humans burn up all fossil fuels is pertinent today, he says, because global emissions continue to climb despite decades of talk about cuts.
There is increasing international pressure to commit to significant cuts in carbon dioxide, the leading greenhouse gas linked to global warming. German Chancellor Angela Merkel has been pushing her G-8 colleagues to agree that the world needs to cut CO2 emissions in half, relative to 1990 levels, by 2050. The United States has rejected the idea and Prime Minister Stephen Harper is under fire for not committing to the proposed target.
Leading scientists have also been calling for dramatic cuts, saying the climate system is coming perilously close to a tipping point, after which unstoppable global warming could melt polar ice, raise sea levels, trigger mass extinctions, and leave billions of people hungry, thirsty and homeless.
The data in Montenegro's study were based on two different models, which have also been used to generate simulations for a recent report from a United Nations intergovernmental panel on climate change. The models, developed at the University of Victoria and the Potsdam Institute for Climate Impact Research in Germany, use information about past climates to project how future climates will respond to different circumstances.
The scenario developed by Montenegro's group followed the UN panel's "business as usual" emissions path. According to that projection, oil, gas and coal consumption would continue on its current trajectory until 2100, then taper off over 200 years as supplies dwindle. Some 5,134 billion tonnes of carbon, locked underground for millions of years, would wind up in the global atmosphere.
Supercomputers ran the models for almost three months to calculate how the climate would respond in the 4,500 years after the emissions finally stop. The scientists concluded that average temperatures around the globe would soar 6-8 C and would remain at least five degrees higher than pre-industrial levels for more than 5,000 years.
About 75 per cent of CO2 emissions released by burning all fossil fuels would persist in the atmosphere for an average of 1,800 years before being soaked up by forests, crops or the oceans, the Victoria study reports. The rest could take much longer than 5,000 years to be absorbed.
The massive release of carbon into the atmosphere would cause oceans to become significantly more acidic and affect the food chain. It would also change how the seas absorb and release carbon for thousands of years, the researchers say.
The results "indicate that the long-term consequences of anthropogenic climate change may be much greater that previously thought," concludes the study, which likens the carbon threat to the threat posed by nuclear waste because the impacts are so serious and long-lived.
Climate models are not perfect and are less reliable the farther into the future they extend, but scientists say they are the only available means of exploring different scenarios. "There is enough uncertainty that the future could play out differently," Montenegro acknowledged in an interview. "But it's the best we can do."
© The Vancouver Sun 2007
