Hot off the press. It’s our fault alright…….

8 03 2013

Meeting Mark Cochrane is turning out to be one of the most valuable and fascinating markcochrane2things I have yet to do online……  the man is a genius at explaining the most difficult issues, and he’s just put out another gem over at the PP website.

It’s not only correlation versus causation – we have correlation and physical, tested processes which strongly support causation unless there is some offsetting physics that no one has discovered.

Where’s the evidence humans are changing the climate?

New results out in Science today, Marcott et al. 2013 (link)

Our results indicate that global mean temperature for the decade 2000–2009 (34) has not yet exceeded the warmest temperatures of the early Holocene (5000 to 10,000 yr B.P.). These temperatures are, however, warmer than 82% of the Holocene distribution as represented by the Standard5×5 stack, or 72% after making plausible corrections for inherent smoothing of the high frequencies in the stack (6) (Fig. 3). In contrast, the decadal mean global temperature of the early 20th century (1900–1909) was cooler than >95% of the Holocene distribution under both the Standard5×5 and high-frequency corrected scenarios. Global temperature, therefore, has risen from near the coldest to the warmest levels of the Holocene within the past century, reversing the long-term cooling trend that began ~5000 yr B.P. Climate models project that temperatures are likely to exceed the full distribution of Holocene warmth by 2100 for all versions of the temperature stack (35) (Fig. 3), regardless of the greenhouse gas emission scenario considered (excluding the year 2000 constant composition scenario, which has already been exceeded). By 2100, global average temperatures will probably be 5 to 12 standard deviations above the Holocene temperature mean for the A1B scenario (35) based on our Standard5×5 plus high-frequency addition stack

Quick translation – the planet had been cooling for 5000 years and through orbital mechanics models of Milankovitch cycles should still be cooling but all of a sudden the temperature shoots up for no apparent reason just when we start pumping CO2 into the atmosphere. We shot from one of the coolest periods in the entire Holocene (11,500 years since the last Ice Age) to close to one of the warmest. Unprecedented rate of change. Any competing theories on why? (crickets…)Standard_deviation_diagram.svg

Take a look at the probabilities associated with being 5-12 standard deviations (normal distribution) above the Holocene mean by 2100.

I posted this diagram of Standard Deviation last year  to explain the possibilities of being three standard deviations out, but five to twelve?  That doesn’t even compute on a graph such as this…  Wikipedia only give probabilities out to the 7th standard deviation from the mean but that is a start.  Cl stands for Central Limits by the way….  that dark blue area.

zσ Percentage within CI Percentage outside CI Fraction outside CI
0.674490σ 50% 50% 1 / 2
0.994458σ 68% 32% 1 / 3.125
68.2689492% 31.7310508% 1 / 3.1514872
1.281552σ 80% 20% 1 / 5
1.644854σ 90% 10% 1 / 10
1.959964σ 95% 5% 1 / 20
95.4499736% 4.5500264% 1 / 21.977895
2.575829σ 99% 1% 1 / 100
99.7300204% 0.2699796% 1 / 370.398
3.290527σ 99.9% 0.1% 1 / 1,000
3.890592σ 99.99% 0.01% 1 / 10,000
99.993666% 0.006334% 1 / 15,787
4.417173σ 99.999% 0.001% 1 / 100,000
4.891638σ 99.9999% 0.0001% 1 / 1,000,000
99.9999426697% 0.0000573303% 1 / 1,744,278
5.326724σ 99.99999% 0.00001% 1 / 10,000,000
5.730729σ 99.999999% 0.000001% 1 / 100,000,000
99.9999998027% 0.0000001973% 1 / 506,797,346
6.109410σ 99.9999999% 0.0000001% 1 / 1,000,000,000
6.466951σ 99.99999999% 0.00000001% 1 / 10,000,000,000
6.806502σ 99.999999999% 0.000000001% 1 / 100,000,000,000
99.9999999997440% 0.000000000256% 1 / 390,682,215,445

The bottom row (in bold) shows the probability of any point occurring seven standard deviations from the mean, the probability is one in 390 plus billion.  http://en.wikipedia.org/wiki/Standard_deviation

The most likely scenario, five standard deviations, has a probability of one in 1.7 million….  get it?  The chances that the current warming rate is natural, ie not our fault, is like winning the lotto.

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