Scientists predict 100 years of warming
Margaret Munro
CanWest News Service
July 19, 2005
This year's wacky weather may be nothing compared to the climatic future that awaits today's children and their families.
A study published Monday in the Proceedings of the National Academy of Sciences says the current generation has so altered the global atmosphere that it has ensured the vagaries of global warming will continue for at least the next 100 years.
Even if today's consumers stopped burning fossil fuels tomorrow, the carbon dioxide they have pumped into the air since 1980 will linger until 2100. "There is a commitment to additional CO2-induced warming even in the absence of emissions," the study says.
Scientists have long warned that carbon dioxide, which acts like a greenhouse, trapping heat in the atmosphere, is long-lived. But this is the first study to point the finger at the current generation as the biggest carbon dioxide producer ever. Burning of gas and fossil fuels in vehicles, furnaces and factories is the leading source of man-made carbon dioxide.
"The 1975-2000 generation alone increased atmospheric CO2 by approximately 45 ppm [parts per million], more than half of the total increase over the industrial era," the researchers report.
The level of carbon dioxide in the atmosphere was near 285 ppm in the 1850s before people began burning coal, oil and gas in a big way. It is now close to 380 ppm and atmospheric scientists say it could hit 500 ppm by 2050 if carbon dioxide production is not curbed dramatically.
Rising carbon dioxide levels are already linked with warmer temperatures and are expected to trigger a rise in the average global temperature of 1.5 to three degrees Celsius over the next century. Scientists predict the change will have dramatic impacts in areas such as the Canadian North, where permafrost is already melting. The warming is also expected to alter weather patterns and increase extreme and unusual weather events like hurricanes and droughts.
Solomon and Friedlingstein's analysis shows how each generation since 1900 has added to the carbon dioxide concentration, and passed "warming commitments" on to its children, grandchildren and later descendants.
They divided the past 150 years into six generations of 25 years each and applied two cases -- no further emissions or constant emissions -- to each generation to evaluate warming effects on successive generations. They conclude that the current generation has had by far the biggest impact, and one that will translate into additional CO2-induced climate change for decades to come.
Scientists say the oceans will absorb most of the carbon that has been dug out of the ground over the last 150 years and pumped into the air, but predict the process will take thousands of years.
© The Vancouver Sun 2005 |
