Eighty percent of Philippines could sink in the next 80 years. And it is not because of the greed and corruption of our politicians. It is because of global warming.
A one-meter increase in sea levels will sink 64 of the country’s 80 provinces, the environment group Greenpace projected in 2010.
On Sept. 27, this year, in Stockholm, Sweden, the Intergovernmental Panel on Climate Change released its fifth report on global warming. (The fourth report was issued in 2007).
In the Summary for Policymakers, the IPCC makes the following conclusions:
—The global mean sea level will continue to rise during the 21st century, by .4 (the best scenario) to .7 meter (the worst scenario) by 2100.
The rate of rise in sea level has doubled during the 20th century. Sea levels are rising faster now than in the previous two millennia, and the rise will continue to accelerate
—regardless of the emissions scenario, even with strong climate change mitigation.
A much more rapid sea level rise is now projected (28 to 98 cm by 2100). This is more than 50 percent higher than the old projections (18-59 cm) made by the IPCC in in its previous reports.
—Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850.
—In the Northern Hemisphere, 1983-2012 was likely the warmest 30-year period of the last 1400 years (medium confidence).
—Warming in the climate system is unequivocal.
—Global surface temperature change for the end of the 21st century is likely to exceed 1.5ºC relative to 1850 for all four global warming scenarios designed by the IPCC. The worst scenario shows a temperature increase exceeding 4ºC–double the 2ºC dangerous level of global warming. The 2ºC is the dividing line between tolerable global warming and dangerous global warming, which could mean the Greenland ice sheet would disappear, the Arctic Ocean would be ice-free in summer, and oceans would be acidic.
—Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions.
The IPCC placed that limit at one trillion tons, the amount of greenhouse gas emissions humans must emit until the year 2100, just so mankind would have a two-thirds chance of reaching the 2ºC threshold. If the one-trillion-ton carbon quota is exceeded, the world will warm by 2ºC.
Unfortunately, of the one trillion tons, mankind has already emitted 521 billion tons, as of 2011, leaving less than 500 billion tons in allowable pollution for the next 87 years.
Says The Economist: “At current rates of greenhouse-gas emission, the rest of the budget will have been spent before 2040. The odds of keeping the eventual rise in global temperatures to below 2ºC will lengthen—even if climate sensitivity is lower than was thought and even if the pause in surface air temperatures persists for a while.” Since 1990, the Earth has been warming at the rate of 0.15°C per decade or by 1.5°C by 2090. The world can tolerate an increase in temperature per century of only 2°C.—the dividing line between tolerable global warming and dangerous global warming.
“Global surface temperature change for the end of the 21st century is projected to be likely to exceed 1.5°C relative to 1850 to 1900 in all but the lowest scenario considered, and likely to exceed 2°C for the two high scenarios,” warns Thomas Stocker, chair of Working Group I that prepared the physical science of the IPCC report.
“Heat waves are very likely to occur more frequently and last longer. As the Earth warms, we expect to see currently wet regions receiving more rainfall, and dry regions receiving less, although there will be exceptions,” he adds.
“It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century. The evidence for this has grown, thanks to more and better observations, an improved understanding of the climate system response and improved climate models,” says the IPCC report.
“The atmosphere and ocean have warmed, the amount of snow and ice has diminished, the global mean sea level has risen and the concentrations of greenhouse gases have increased,” says Qin Dahe, co-chair of IPCC Working Group I.
Stocker says: “Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions.”
The IPCC made four scenarios of future greenhouse gas concentrations and aerosols, spanning a wide range of possible futures. The Working Group I report assessed global and regional-scale climate change for the early, mid, and later 21st century.
IPCC says “global surface temperature change for the end of the 21st century is projected to be likely to exceed 1.5ºC relative to 1850 to 1900 in all but the lowest scenario considered, and likely to exceed 2ºC for the two high scenarios.”
“As the ocean warms, and glaciers and ice sheets reduce, global mean sea level will continue to rise, but at a faster rate than we have experienced over the past 40 years,” says Qin Dahe. The report finds with high confidence that ocean warming dominates the increase in energy stored in the climate system, accounting for more than 90% of the energy accumulated between 1971 and 2010.
Per IPPC speak, virtually certain means 99 percent to 100 percent probability, extremely likely: 95 percent to 100 percent, very likely: 90 percent to 100 percent, likely: 66 percent to 100 percent.
The IPCC “is categorical in its conclusion: climate change has not stopped and man is the main cause.”
The IPCC report, notes The Economist, “is more definitive than in the past about the role of people in causing climate change.”
IPCC now says it is “extremely likely,” or a probability of over 95 percent, that humans are causing global warming.
This, The Economist points out, contrasts with the tentative tone of the early IPCC reports.
“The observed increase [in surface air temperatures]could be largely due to this natural variability,” said the first one, in 1990. The next report in 1995 merely suggested a link between rising temperatures and human activity. That link was deemed “likely” (which means probability of 66 percent) in 2001, and “very likely” (90 percent) in 2007.
The 2013 IPCC report identifies radiative forcing, the difference between the amount of heat coming into the climate and the amount reflected back, as the immediate cause of warming. Radiative forcing is expressed in watts per square metre (W/m2), a unit of energy. A rise indicates that heat is building up in the system.
Total radiative forcing from man-made sources since 1750 (which is before industrialization) has risen from 0.29-0.85W/m2 in 1950 to 0.64-1.86W/m2 in 1980 to 1.13-3.33W/m2 in 2011.
The average has jumped from 0.57 to 1.25 to 2.29, respectively—a four-fold increase in 60 years, reckons The Economist.
One big change recently, IPCC notes, is that the cooling effect of aerosols seems to have been less strong than it used to be. But there is no sign that the rise in radiative forcing has slowed during the past 15 years of flat surface temperatures. The best estimate for total man-made radiative forcing in 2011 is 43 percent above 2005 levels.
“Ocean warming,” the IPCC report says, “is largest near the surface and the upper 75 meters warmed by 0.11ºC per decade over the period 1971-2010.” It adds that more than 60 percent of the net energy increase in the climate system is stored in the upper ocean (0-700 metres)—and about 30 percent is stored in the ocean below 700 meters.
The IPCC says it is “very likely that the mean rate of global average sea level rise was 1.7mm a year between 1901 and 2010, 2.0mm a year between 1971 and 2010 and 3.2mm a year between 1993 and 2010.”
The summary report has 259 authors from 39 countries. The Working Group I that prepared the Summary for Policymakers was chaired by Qin Dahe and Thomas Stocker.
Qin Dahe is with the China Meteorological Administration, Beijing, China. Stocker is with the University of Bern, Switzerland.