back of the envelope analysis
Oct. 11th, 2014 02:09 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
ljgeoffBack in 2010 on so, when I was just getting my head around the catastrophe of climate change, I said, I'll wait until 2015 and then reassess. It's not 2015, but it's close enough, hey? What does the future look like now? What's the consensus? What were the projections and how do they line up with where we are?
Sea Level: From A new view on sea level rise, Stefan Rahmstorf (2010) "In its 2007 report, the Intergovernmental Panel on Climate Change (IPCC) projected a global sea level rise of 18 to 59 centimetres from 1990 to the 2090s, plus an unspecified amount that could come from changes in the large ice sheets covering Greenland and Antarctica." Averaging that figure over 100 years gives a ballpark of .18-.59 centimeters per year.
The reality: From Climate Change Indicators in the United State (US Environmental Protection Agency, last updated on 7/2/2014) "Since 1993, however, average sea level has risen at a rate of 0.11 to 0.12 inches per year—roughly twice as fast as the long-term trend."
Converting inches to centimeters, the above quote would read: "Since 1993, however, average sea level has risen at a rate of 0.28 to 0.30 centimeters per year—roughly twice as fast as the long-term trend."
Verdict: Yep. Since sea level rise will be an exponential function, scientists are now projecting a 2-3 meter (6.5-10 ft) sea level rise by 2100, with uncertainty due to mankind's actions to reduce CO2 emissions. A business-as-usual model projects a 6 meter (19.6 feet) rise in sea level due mostly to sudden collapse of the WAIS.
Polar Ice:
The dotted line in the mean model projection, and the red line is where we are.
Verdict: Yep. Arctic ice is decreasing faster than projections.
Shifting Hydrology: Anecdotally, one has only to look this map to see the effects of shifting bands of hydrology:
"In July 2014, short-term global drought conditions remained relatively constant over most of the globe. Asia saw drought intensify slightly in and around central Russia while conditions eased slightly in central India. In China, drought in the North China Plain may lower the corn harvest for the first time since 2009. In Africa, drought remains entrenched in the equatorial region as well as on Madagascar. In Somalia, worsening drought conditions have led the government to issue and urgent call for aid in the form of food, water, and medication. In North America, drought remains mainly focused on the American Southwest and Southern Plains where large wildfires have developed and are burning. In South America, drought remained consistent around the equator but improved slightly in southern Argentina. In Brazil, drought continues and Brazil’s Public Ministry recommended that Sao Paulo state begin rationing water immediately. In Europe, drought remains largely steady with some drying around the Baltic Sea. In Australia, drought continues mainly in the East. The drought has led experts to estimate that Australian cotton production will be roughly cut in half for the 2014-2015 season. Northern areas of Oceana saw slight improvement in drought conditions."
In his Feb 28, 2014 statement to US Congress, John P. Holdren quotes several studies that outlines the complexity of how hydrology bands are shifting, and how drought and precipitation are becoming more extreme.
Verdict: Yep. Hydrological bands are shifting, and weather is becoming more extreme.
Ocean Acidity: From Modern ocean acidification is outpacing ancient upheaval: Rate may be ten times faster (June 2, 2014) "Scientists estimate that surface ocean acidity increased by about 100 percent during the Paleocene-Eocene Thermal Maximum in a few thousand years or more, and stayed that way for the next 70,000 years. Scientists have long suspected that ocean acidification caused the crisis -- similar to today, as humanmade CO2 combines with seawater to change its chemistry. Now, for the first time, scientists have quantified the extent of surface acidification from those ancient days, and the news is not good: the oceans are on track to acidify at least as much as they did then, only at a much faster rate."
Verdict: Yep. Ocean acidity is increasing at horrific rates.
Amazon Rain Forest: In a February 2010 report, the World Bank estimated that the "tipping point" for the Amazon could be approximately 20% deforestation. If reached, this threshold could trigger a dramatic die-back of the Amazon rain forest. With 17% to 18% of the Amazon already deforested, another similar amount degraded, forest fires running rampant, and global temperatures already on the rise, the Amazon ecosystem could face ecological collapse sooner than previously expected.
Aggregated deforestation in the Brazilian Amazon from 1988-2013
As a ballpark figure, since the Amazon has approx. 5 million sq kilometers, and the above graphic is documenting a little over 400,000 sq kilometers of aggregated deforestation, we're currently at 12.5% deforestation -- more than half way there. The good news is that the rate of deforestation is going down. But, as temperatures over land masses increase, drought and fire will likely increase the level of deforestation.
Verdict: Probably. From the above linked article: "Much of current scientific opinion suggests that intact tropical forests may be quite resilient to climate change," Professor Yadvinder Malhi, from the Oxford University's Environmental Change Institute, told BBC News. "But the combination of climate change, land-use change and fire may be much more destructive."
WAIS: The inevitable melting of the WAIS became pretty big new this year. Professor Eric Rignot of University of California Irvine is quoted as commenting on retreats of the Pine Island and Thwaites Glaciers “This is not an unprecedented rate of retreat,” said Professor Rignot, “but for the West Antarctic ice sheet, this is what you might refer as a tipping point.”
Verdict: Yep.
Okay, I've spent all morning doing this and it's too long but there ya go. What does this mean? Well, we're fucked. This is happening. It's not going to stop happening in my lifetime. It might slow down in my childrens' lifetime, I dunno. My gut feeling is that we won't have time or will to slow it down by our own initiative; collapse of the current system will be what slows it down.
Sea Level: From A new view on sea level rise, Stefan Rahmstorf (2010) "In its 2007 report, the Intergovernmental Panel on Climate Change (IPCC) projected a global sea level rise of 18 to 59 centimetres from 1990 to the 2090s, plus an unspecified amount that could come from changes in the large ice sheets covering Greenland and Antarctica." Averaging that figure over 100 years gives a ballpark of .18-.59 centimeters per year.
The reality: From Climate Change Indicators in the United State (US Environmental Protection Agency, last updated on 7/2/2014) "Since 1993, however, average sea level has risen at a rate of 0.11 to 0.12 inches per year—roughly twice as fast as the long-term trend."
Converting inches to centimeters, the above quote would read: "Since 1993, however, average sea level has risen at a rate of 0.28 to 0.30 centimeters per year—roughly twice as fast as the long-term trend."
Verdict: Yep. Since sea level rise will be an exponential function, scientists are now projecting a 2-3 meter (6.5-10 ft) sea level rise by 2100, with uncertainty due to mankind's actions to reduce CO2 emissions. A business-as-usual model projects a 6 meter (19.6 feet) rise in sea level due mostly to sudden collapse of the WAIS.
Polar Ice:
The dotted line in the mean model projection, and the red line is where we are.
Verdict: Yep. Arctic ice is decreasing faster than projections.
Shifting Hydrology: Anecdotally, one has only to look this map to see the effects of shifting bands of hydrology:
"In July 2014, short-term global drought conditions remained relatively constant over most of the globe. Asia saw drought intensify slightly in and around central Russia while conditions eased slightly in central India. In China, drought in the North China Plain may lower the corn harvest for the first time since 2009. In Africa, drought remains entrenched in the equatorial region as well as on Madagascar. In Somalia, worsening drought conditions have led the government to issue and urgent call for aid in the form of food, water, and medication. In North America, drought remains mainly focused on the American Southwest and Southern Plains where large wildfires have developed and are burning. In South America, drought remained consistent around the equator but improved slightly in southern Argentina. In Brazil, drought continues and Brazil’s Public Ministry recommended that Sao Paulo state begin rationing water immediately. In Europe, drought remains largely steady with some drying around the Baltic Sea. In Australia, drought continues mainly in the East. The drought has led experts to estimate that Australian cotton production will be roughly cut in half for the 2014-2015 season. Northern areas of Oceana saw slight improvement in drought conditions."
In his Feb 28, 2014 statement to US Congress, John P. Holdren quotes several studies that outlines the complexity of how hydrology bands are shifting, and how drought and precipitation are becoming more extreme.
Verdict: Yep. Hydrological bands are shifting, and weather is becoming more extreme.
Ocean Acidity: From Modern ocean acidification is outpacing ancient upheaval: Rate may be ten times faster (June 2, 2014) "Scientists estimate that surface ocean acidity increased by about 100 percent during the Paleocene-Eocene Thermal Maximum in a few thousand years or more, and stayed that way for the next 70,000 years. Scientists have long suspected that ocean acidification caused the crisis -- similar to today, as humanmade CO2 combines with seawater to change its chemistry. Now, for the first time, scientists have quantified the extent of surface acidification from those ancient days, and the news is not good: the oceans are on track to acidify at least as much as they did then, only at a much faster rate."
Verdict: Yep. Ocean acidity is increasing at horrific rates.
Amazon Rain Forest: In a February 2010 report, the World Bank estimated that the "tipping point" for the Amazon could be approximately 20% deforestation. If reached, this threshold could trigger a dramatic die-back of the Amazon rain forest. With 17% to 18% of the Amazon already deforested, another similar amount degraded, forest fires running rampant, and global temperatures already on the rise, the Amazon ecosystem could face ecological collapse sooner than previously expected.
Aggregated deforestation in the Brazilian Amazon from 1988-2013As a ballpark figure, since the Amazon has approx. 5 million sq kilometers, and the above graphic is documenting a little over 400,000 sq kilometers of aggregated deforestation, we're currently at 12.5% deforestation -- more than half way there. The good news is that the rate of deforestation is going down. But, as temperatures over land masses increase, drought and fire will likely increase the level of deforestation.
Verdict: Probably. From the above linked article: "Much of current scientific opinion suggests that intact tropical forests may be quite resilient to climate change," Professor Yadvinder Malhi, from the Oxford University's Environmental Change Institute, told BBC News. "But the combination of climate change, land-use change and fire may be much more destructive."
WAIS: The inevitable melting of the WAIS became pretty big new this year. Professor Eric Rignot of University of California Irvine is quoted as commenting on retreats of the Pine Island and Thwaites Glaciers “This is not an unprecedented rate of retreat,” said Professor Rignot, “but for the West Antarctic ice sheet, this is what you might refer as a tipping point.”
Verdict: Yep.
Okay, I've spent all morning doing this and it's too long but there ya go. What does this mean? Well, we're fucked. This is happening. It's not going to stop happening in my lifetime. It might slow down in my childrens' lifetime, I dunno. My gut feeling is that we won't have time or will to slow it down by our own initiative; collapse of the current system will be what slows it down.