Less than two-tenths of one-percent.
Another 108 years transpire between 1850 and NOAA's initiation of CO2 measurement at the Muana Loa Observatory. CO2 increased 12.4% over that period. The Muana Loa data series is now 52 years old. It documents a 22.6% increase in CO2.
- Aristotle to mid 19th century (2,185 years): +0.18%
- Mid 19th century to beginning of Muana Loa series (108 years): +12.4%
- 1958 through 2009 (52 years): +22.6%
1. What level of CO2 is considered dangerous enough to merit decisive action?
2. When will such levels be reached?
What level of CO2 is considered dangerous enough to merit decisive action?
This is, obviously, the big question. While there is broad international agreement on existence of an epic problem, progress to-date has been defined mostly by inaction.
350ppm - Dr. James Hansen preceded Al Gore by over a decade as a leading voice for meaningful change. He put his career at risk and some of his early findings, limited at the time by available science, were subsequently proven. Hansen votes for 350ppm as the tolerable maximum level and says "...If we follow business as usual I can't see how west Antarctica could survive a century. We are talking about a sea-level rise of at least a couple of metres this century." The 350ppm goal has been popularized by 350.org, which provides a summary of climate science here. The Pew Center maintains a climate advocacy site. RealClimate is the most thoughtful climate science site.
While climate change remediation advocates generally agree on 350ppm as the acceptable maximum level, they almost universally forget to mention close correlation between economics and carbon. Criticism of the U.S. dwells on our 5% of world population producing 20% of CO2. Left unsaid is that we also contribute 20% of global GDP. We crossed the 350ppm level 22 years ago; only six years after China reformed and opened its economy. China's economy is now 12-times larger than it was 22-years ago. Since Wikipedia has a decent overview of economics as climate driver, TheRaven wonders why the remediation advocates don't get it.
400ppm - this is a funny number. Either side of the debate gravitates to 350 or 450, with 400 left to bloggers like this one, who, funnily enough, is also looking at CO2 growth trend. This blogger looks at CO2 from a peak oil perspective and NOAA keeps a running tab.(Note to NOAA and other government agencies - really love the data, you're doing great work, suggest you stop short-selling yourselves with crappy charts.)
The point on 400 ppm is that it's far below long-term targets set by international agreement but well above a comfortable level according to remediation advocates and concerned experts. Hansen completely rejects Europe's 550 ppm target, yet Europe's target is more aggressive than ours. This blog looks at some detail, has better charts that the government and provides footnotes & sources.
450ppm - ClimateProgress wonders if stopping CO2 at 450ppm is politically possible. Hansen's take on 450ppm is that "...it will probably melt all the ice - that's a sea rise of 75 metres. What we have found is that the target we have all been aiming for is a disaster - a guaranteed disaster...". MIT's Center for Global Change Science developed a climate model that "...looks in great detail at the effects of economic activity coupled with the effects of atmospheric, oceanic and biological systems...". The model was run 400 times. Aggregated results point to high probability of incredible increases in global temperatures. Results were peer-reviewed.
When will such levels be reached?
350ppm - we crossed this line 22 years ago. The decade just ended was that warmest on record. Coincidence?
400ppm - TheRaven extended 52 years of monthly CO2 readings with only a 1% forecast increase in annual CO2 growth. Such assumption is far below historic growth in global GDP. With only a 1% increase in growth rate, 2016 will average more than 400ppm.
450ppm - using the aforementioned 1% increase in growth rates, we cross the global heat Rubicon in 26 years. Considering latent momentum in the $60 trillion global economy, it's simply impossible that CO2 levels will not blast through 450ppm. The mild forecast assumption projects 485ppm by 2050.
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Can it get worse?
2008 was a tough year for the global economy. GDP growth ranged from under 1% for the EU to 9% for China. Global GDP growth was still 3.2% in a tough year. Global GDP growth averaged 4.3% between 1998 and 2003. Accelerating growth in the global middle class may contribute to acceleration of overall growth economic growth.
If we change the forecast assumption from 1% annual growth in rate of CO2 increase to 2.5% - a level that is significantly below historic global GDP growth - CO2 levels approach Europe's 550ppm goal in a mere 40 years. With the higher growth assumption, we permanently cross 400ppm in 2015 and cruise past 450pm in only 22 years.
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MIT's published results point to as much as a 9 degree (Fahrenheit) increase in average global temperature.
Yes, it can get worse.
Yes, it can get worse.
**************************************UPDATE Aug. 4, 2010: If you live in Russia, it's gotten worse. A lot worse. The Economist weighs in with an insightful analysis of how media is screwing up reporting on climate change.