Politicians, business people, and private individuals worldwide now have a new framework-of-expectations to work with. The most intensely peer-reviewed report on global warming, and its present, short and long term consequences, has been released - or, at least its first volume has (all 1,600 pages of it, with the remaining three volumes being released successively throughout 2007).
The important thing to understand in regards to this report is the way it has been produced. Every single aspect of the study has been subject to intense peer-review. If something could not be conclusively proved, it is omitted. The final content of the report is therefore not only regarded as correct, but also likely to be a conservative rendering of the facts. Additionally, because of the time frames involved with this filtering process, the report is regarded by some as already a year or more out of date, with some of the recent heightened awareness of the accelerating rate of glacial melt, for example, not having time to get incorporated. But, even in this conservative state, the report is impossible to ignore.
The world's leading climate scientists, in their most powerful language ever used on the issue, said global warming is "very likely" man-made, according to a new report obtained Friday by The Associated Press.... The phrase "very likely" translates to a more than 90 percent certainty that global warming is caused by man. What that means in layman's language is "we have this nailed," said top U.S. climate scientist Jerry Mahlman, who originated the percentage system.... - CNN
The BBC gives some inference about the report being conservative:
By "very likely", the IPCC means greater than 90% probability. The scientific body, in a report released in Paris, forecasts temperatures will probably rise by between 1.8-4C (3.2-7.2F) by 2100. But another study released on the eve of publication suggests its previous reports may have been too conservative. - BBC
If you had a ninety percent chance your house was going to be burgled, I'm pretty sure your insurance premiums would be paid in full, and on time, every month. In fact, you'd likely move to another neighbourhood as well, if you could! This is where we're at today. We need to think ahead, and reassess our lifestyles and direction.
Global warming over the past half century has been nearly twice that of the century as a whole. In the northern hemisphere, temperatures were very probably higher over the second part of 20th century than at any 50-year period in the last 500 years and probably the highest in at least the past 1,300 years. Eleven of the past 12 years rank among the dozen warmest years on record.... -- Global warming "is now evident" from several sources. Ocean warming now extends to a depth of at least 3,000 metres (9,750 feet) as the seas take up heat from the air. Mountain glaciers and snow cover have declined in both hemispheres. Sea levels rose globally by 1.8 millimetres (0.07 inches) per year from 1961 to 2003 but this pace accelerated to 3.1 mm (0.12 inch) per year from 1993 to 2003. Most of the rise was due to thermal expansion because water expands when it warms. The rest was due to runoff from glacier and snow melt. -- Since the 1970s droughts have been "more intense and longer" and observed over wider areas, especially in the tropics and subtropics. -- From 1900 to 2005, rainfall increased "significantly" in eastern parts of North and South America, northern Europe and northern and central Asia, while drying occurred in the Sahel, Mediterranean, southern Africa and parts of southern Asia. -- The top layers of the Arctic permafrost have warmed by up to 3.0 degrees C (5.4 degrees F) since the 1980s. The maximum area of seasonally frozen ground has decreased by around seven percent in the northern hemisphere since 1900. FORECAST FOR 21ST CENTURY: -- By 2100, global average surface temperatures could rise by between 1.1 C (1.98 F) and 6.4 C (11.52 F) compared to 1980-99 levels. These figures come from computer simulations based on how much carbon dioxide (CO2), the principal greenhouse gas, is in the air. The lower figure is the "B1 scenario", which is based on a fast-track switch to cleaner energy and sustainable development. The higher figure is the "A1F1 scenario", in which fossil fuels are still burned intensively. -- Inside this broad temperature range, the most likely surface temperature rise will be between 1.8 and 4.0 degrees C (3.24 and 7.2 degrees F). In 2001, the IPCC predicted a range of between 1.4 and 5.8 degree C (2.52 and 10.4 degrees F). -- Sea levels will rise by between 18 and 58 centimetres (7.2 and 23.2 inches), again based on how much CO2 is in the air. In the 2001 report, the estimate was 9.0 to 88 cms (3.5 to 35 inches). The IPCC says the revision is because of improved estimates as to how the oceans absorb heat. -- Warming will occur most over land at high northern latitudes and least over the Southern Ocean and the North Atlantic. -- Higher CO2 levels will lead to increasing acidification of the oceans, whose micro-organisms absorb carbon dioxide at the surface. -- Snow cover will contract further and the depth of thaw in most permafrost reasons will increase. Sea ice is projected to shrink in both the Arctic and Antarctic under all CO2 models. In some projections, the Arctic will be virtually free of late summer sea ice by the latter part of the 21st century. -- Hot extremes, heatwaves and heavy precipitation events are "very likely" to become more frequent. -- Typhoons and hurricanes are likely to become more powerful, packing higher wind speeds and more intense rainstorms but the evidence about whether they may decrease in number is inconclusive. Extra-tropical storms will track poleward. -- The Gulf Stream is "very likely" to slow down. Projections suggest an average slowdown of some 25 percent during the 21st century. But this should not plunge western Europe into a new Ice Age. Higher air temperatures will help compensate for the loss of warmth from this balmy Atlantic current. -- Antarctica: There is no evidence at the moment that the Antarctic icesheet will suffer widespread melting this century as it is such a huge, cold mass. Some studies project it will gain in mass due to increased snowfall. But others suggest a net loss of mass if coastal glaciers start to run more swiftly. BEYOND THE 21ST CENTURY: -- Carbon emissions this century "will contribute to warming and sea-level rise for more than a millennium", due to the timescale required for greenhouse gases to degrade. -- The Greenland icesheet will continue to contract beyond 2100 and contribute to the global sea level rise. Models suggest a rise of 1.9 to 4.6 degrees C (3.42 to 8.3 degrees F) in global average temperatures compared to pre-industrial times would, if sustained for millennia, virtually eliminate the Greenland icesheet and drive up sea levels by seven metres (22.75 feet). AREAS OF CERTAINTY AND UNCERTAINTY: -- The IPCC says it has greater confidence in the accuracy of its short-term projections. It had predicted warming of between 0.15 and 0.3 degrees C (0.27 and 0.54 degrees F) per decade for 1990-2005. The warming turned out to be 0.2 degrees C (0.36 degree F), right in the middle of the range. -- It also says it can forecast with greater confidence rises in temperature, rainfall, extreme weather events and ice response at regional level. -- Positive feedbacks: These are events that could swiftly increase global warming by dumping into the atmosphere greenhouse gases that have been stored, for instance, in the soil or by slowing or stopping processes that absorb CO2 from the air. Positive feedbacks are poorly understood. "The magnitude ... is uncertain" and this makes it hard to accurately project scenarios at which CO2 will stabilise, which is a key factor in policymaking. - WBCSD
Possibly the most significant effect of the report, we hope, will be to finally end the unbalanced media attention that has been given to climate change deniers in the past. While politicians and public are convinced global warming is a heated scientific debate, attempts at finding solutions will always be met with apathy, or scorn. This report shows there is no debate. It's over. We can now get on with the job at hand. Our next great obstacle is dealing with our own minds. Further Reading:
Politicians, business people, and private individuals worldwide now have a new framework-of-expectations to work with. The most intensely peer-reviewed report on global warming, and its present, short and long term consequences, has been released - or, at least its first volume has (all 1,600 pages of it, with the remaining three volumes being released successively throughout 2007).Eleven of the past 12 years rank among the dozen warmest years on record.... -- Global warming "is now evident" from several sources. Ocean warming now extends to a depth of at least 3,000 metres (9,750 feet) as the seas take up heat from the air. Mountain glaciers and snow cover have declined in both hemispheres. Sea levels rose globally by 1.8 millimetres (0.07 inches) per year from 1961 to 2003 but this pace accelerated to 3.1 mm (0.12 inch) per year from 1993 to 2003. Most of the rise was due to thermal expansion because water expands when it warms. The rest was due to runoff from glacier and snow melt. -- Since the 1970s droughts have been "more intense and longer" and observed over wider areas, especially in the tropics and subtropics. -- From 1900 to 2005, rainfall increased "significantly" in eastern parts of North and South America, northern Europe and northern and central Asia, while drying occurred in the Sahel, Mediterranean, southern Africa and parts of southern Asia. -- The top layers of the Arctic permafrost have warmed by up to 3.0 degrees C (5.4 degrees F) since the 1980s. The maximum area of seasonally frozen ground has decreased by around seven percent in the northern hemisphere since 1900. FORECAST FOR 21ST CENTURY: -- By 2100, global average surface temperatures could rise by between 1.1 C (1.98 F) and 6.4 C (11.52 F) compared to 1980-99 levels. These figures come from computer simulations based on how much carbon dioxide (CO2), the principal greenhouse gas, is in the air.
The lower figure is the "B1 scenario", which is based on a fast-track switch to cleaner energy and sustainable development. The higher figure is the "A1F1 scenario", in which fossil fuels are still burned intensively. -- Inside this broad temperature range, the most likely surface temperature rise will be between 1.8 and 4.0 degrees C (3.24 and 7.2 degrees F). In 2001, the IPCC predicted a range of between 1.4 and 5.8 degree C (2.52 and 10.4 degrees F). -- Sea levels will rise by between 18 and 58 centimetres (7.2 and 23.2 inches), again based on how much CO2 is in the air. In the 2001 report, the estimate was 9.0 to 88 cms (3.5 to 35 inches). The IPCC says the revision is because of improved estimates as to how the oceans absorb heat. -- Warming will occur most over land at high northern latitudes and least over the Southern Ocean and the North Atlantic. -- Higher CO2 levels will lead to increasing acidification of the oceans, whose micro-organisms absorb carbon dioxide at the surface. -- Snow cover will contract further and the depth of thaw in most permafrost reasons will increase. Sea ice is projected to shrink in both the Arctic and Antarctic under all CO2 models. In some projections, the Arctic will be virtually free of late summer sea ice by the latter part of the 21st century. -- Hot extremes, heatwaves and heavy precipitation events are "very likely" to become more frequent.
-- Typhoons and hurricanes are likely to become more powerful, packing higher wind speeds and more intense rainstorms but the evidence about whether they may decrease in number is inconclusive. Extra-tropical storms will track poleward. -- The Gulf Stream is "very likely" to slow down. Projections suggest an average slowdown of some 25 percent during the 21st century. But this should not plunge western Europe into a new Ice Age. Higher air temperatures will help compensate for the loss of warmth from this balmy Atlantic current. -- Antarctica: There is no evidence at the moment that the Antarctic icesheet will suffer widespread melting this century as it is such a huge, cold mass. Some studies project it will gain in mass due to increased snowfall. But others suggest a net loss of mass if coastal glaciers start to run more swiftly. BEYOND THE 21ST CENTURY: -- Carbon emissions this century "will contribute to warming and sea-level rise for more than a millennium", due to the timescale required for greenhouse gases to degrade. -- The Greenland icesheet will continue to contract beyond 2100 and contribute to the global sea level rise. Models suggest a rise of 1.9 to 4.6 degrees C (3.42 to 8.3 degrees F) in global average temperatures compared to pre-industrial times would, if sustained for millennia, virtually eliminate the Greenland icesheet and drive up sea levels by seven metres (22.75 feet). AREAS OF CERTAINTY AND UNCERTAINTY: -- The IPCC says it has greater confidence in the accuracy of its short-term projections. It had predicted warming of between 0.15 and 0.3 degrees C (0.27 and 0.54 degrees F) per decade for 1990-2005. The warming turned out to be 0.2 degrees C (0.36 degree F), right in the middle of the range. -- It also says it can forecast with greater confidence rises in temperature, rainfall, extreme weather events and ice response at regional level. -- Positive feedbacks: These are events that could swiftly increase global warming by dumping into the atmosphere greenhouse gases that have been stored, for instance, in the soil or by slowing or stopping processes that absorb CO2 from the air. Positive feedbacks are poorly understood. "The magnitude ... is uncertain" and this makes it hard to accurately project scenarios at which CO2 will stabilise, which is a key factor in policymaking. - WBCSD
Nice writing. You are on my RSS reader now so I can read more from you down the road.
Written in August 2008