Digby's Hullabaloo
2801 Ocean Park Blvd.
Box 157
Santa Monica, Ca 90405

Facebook: Digby Parton

@BloggersRUs (Tom Sullivan)

thedigbyblog at gmail
satniteflix at gmail
publius.gaius at gmail
tpostsully at gmail
Spockosbrain at gmail
Richardein at me.com


Mother Jones
Raw Story
Huffington Post
Crooks and Liars
American Prospect
New Republic

Denofcinema.com: Saturday Night at the Movies by Dennis Hartley review archive

January 2003 February 2003 March 2003 April 2003 May 2003 June 2003 July 2003 August 2003 September 2003 October 2003 November 2003 December 2003 January 2004 February 2004 March 2004 April 2004 May 2004 June 2004 July 2004 August 2004 September 2004 October 2004 November 2004 December 2004 January 2005 February 2005 March 2005 April 2005 May 2005 June 2005 July 2005 August 2005 September 2005 October 2005 November 2005 December 2005 January 2006 February 2006 March 2006 April 2006 May 2006 June 2006 July 2006 August 2006 September 2006 October 2006 November 2006 December 2006 January 2007 February 2007 March 2007 April 2007 May 2007 June 2007 July 2007 August 2007 September 2007 October 2007 November 2007 December 2007 January 2008 February 2008 March 2008 April 2008 May 2008 June 2008 July 2008 August 2008 September 2008 October 2008 November 2008 December 2008 January 2009 February 2009 March 2009 April 2009 May 2009 June 2009 July 2009 August 2009 September 2009 October 2009 November 2009 December 2009 January 2010 February 2010 March 2010 April 2010 May 2010 June 2010 July 2010 August 2010 September 2010 October 2010 November 2010 December 2010 January 2011 February 2011 March 2011 April 2011 May 2011 June 2011 July 2011 August 2011 September 2011 October 2011 November 2011 December 2011 January 2012 February 2012 March 2012 April 2012 May 2012 June 2012 July 2012 August 2012 September 2012 October 2012 November 2012 December 2012 January 2013 February 2013 March 2013 April 2013 May 2013 June 2013 July 2013 August 2013 September 2013 October 2013 November 2013 December 2013 January 2014 February 2014 March 2014 April 2014 May 2014 June 2014 July 2014 August 2014 September 2014 October 2014 November 2014 December 2014 January 2015 February 2015 March 2015 April 2015 May 2015 June 2015 July 2015 August 2015 September 2015 October 2015 November 2015 December 2015 January 2016 February 2016 March 2016 April 2016 May 2016 June 2016 July 2016 August 2016 September 2016 October 2016 November 2016 December 2016 January 2017 February 2017 March 2017 April 2017 May 2017 June 2017 July 2017 August 2017 September 2017 October 2017 November 2017 December 2017 January 2018 February 2018 March 2018 April 2018 May 2018 June 2018 July 2018


This page is powered by Blogger. Isn't yours?


Tuesday, February 07, 2017

Global warming has actually reached nearly +1.5°C already

by Gaius Publius

Slide 5 from the "NOAA/NASA Annual Global Analysis for 2016" (pdf here; click to enlarge image). As you'll read below, global temperature in 1910 is a good proxy for "pre-Industrial global temperature." Thus, converting °F in the chart to °C, global warming has reached nearly +1.5°C already. More than +0.2°F (+0.1°C) or that rise came in just the last two years.

In honor of Trumps ascension, it's going to be climate week here at La Maison, just to help get people oriented to where we stand relative to Mother Earth and her interest in having our species around a while longer.

Note as you read, though — this is not fatalistic, yet. There are always things to do before it's too late, and there's not sign, yet, that it's too late. More on the "things to do" in a bit. For now, the state of things.

How to define "pre-Industrial" global temperature

I wrote recently about Trump, climate change and the upward march of global temperature: "Trump Takes Office Following the Three Hottest Years in Recorded History." Now I'd like to extend that idea in a couple of easy charts and one added thought.

The first chart to look at is below. Let's start with a broad look at average global temperature during the Holocene, the period during which our species came out of the Stone Age, became civilized (i.e., lived in settlements; "civilization" has the same root as "city") and entered the modern era.

The Holocene starts around 12,000 years ago, at the end of the most recent ice age, as the last ice receded and the earth warmed to its current temperature range.

Global average temperature during the Holocene. Blue curve: Global temperature reconstruction from proxy data of Marcott et al, Science 2013. Recent instrumental measurements shown in red (global temperature from the instrumental HadCRU data). Graph: Klaus Bitterman. (Source; my annotation; click to enlarge)

In this chart, "zero" on the Y-axis is the average global temperature in the years 1961–1990. The zero point doesn't matter though; what matters is where the most recent low (the "pre-industrial global temperature") is. I've pointed it out in the chart.

("Pre-industrial temperature" refers to the average surface temperature of the earth prior to the start of the Industrial Revolution — the year 1781 when the James Watt steam engine was invented. But it's generally taken to be around 1800, before the climate effects of industrialized coal-burning became apparent. "Pre-Industrial temperature" is a commonly used start point for measuring global warming. A statement like "global warming of +2°C" means "a 2°C increase above pre-Industrial temperature.")

Note, as you look at the chart of the entire Holocene above, that the oldest civilizations, like the Sumerian, date to only 5,000 BCE or so, and proto-writing appears no earlier than about 3,000 BCE or later.Through more than half of this period, humans remained in the Stone Age.

Note also that the Holocene temperature range, from lowest temperature to highest, is no greater than about 0.7°C — less than one full degree of average temperature fluctuation for the entire period. Of course, regional variations have been much greater, but it's the globe as a whole we're concerned about. Thanks to the narrowness of this temperature range, there have always been many places on earth, not just a few, for humans to flourish. Had there been just a few, our population would be much smaller and "civilization" (humans in settlements) would have been much less wide spread.

Put differently, all of human civilization existed on a planet whose average temperature fluctuation was about two-thirds of a degree Celsius. The "pre-Industrial temperature" is also the modern low of that temperature range.

In the next chart, let's look at the end of the above time period, the final 1000 years, in greater detail.

(Source; click to enlarge)

The time frame covers from the year 1000 to about 2013 (2013 is the publication date; the last data sample may be from 2012). The blue line now shows the "PAGES2K" temperature reconstruction, but it gives similar results to the Marcott reconstruction (as discussed by climate scientist Stefan Rahmstorf here).

Note that the global temperature low at about 1900–1910 (the first deep dip in the instrumental readings, the red line) is a good proxy for the pre-industrial temperature low pointed out in the chart. We can take the temperature in that later period (1900 or so) to be nearly the same as the "pre-Industrial low."

Now look at the chart at the very top, from the recent "NOAA/NASA Annual Global Analysis for 2016" (pdf). Note that global average temperature from the low of 1910 to the 2016 high runs from –0.8°F to +1.8°F, a difference of 2.6°F — or 1.44°C — above the 1910 low. (It's a little less in other datasets — for example, see Slide 4 of the same report — but not by enough to matter.)

Two points:
  • The Paris climate agreement had hoped to hold global warming to no more than +1.5°C above the pre-Industrial temperature. This is not going to happen. We're almost at that point now, and we'll breach that goal in just a few years.
  • From the chart at the top, note that the two-year rise from 2014 to 2016 was, converted to Celsius, +0.1 degrees all on its own. Three more two-year periods like this and global temperatures will cross +2°C, the extremely generous IPCC "magic barrier" after which, in lay language, "we're mainly screwed."
This doesn't mean we should do nothing to adapt to the blow — it's always necessary and wise to adapt, even if the start of adaptation is very late. But the window to mitigate — to lessen the blow — is rapidly closing. Remember, once the social and political chaos reaches critical mass (once there's too much of it), global warming will run to its natural conclusion.

Elsewhere I've predicted the "natural conclusion," barring conscious intervention, to be global warming of +7°C before humans are forced to stop emitting so much CO2, either through greatly diminished numbers, or greatly diminished technology, or both.

Global average temperature and Donald Trump

Now the added thought. As of this minute, we humans aren't slowing or stopping our carbon emissions. We continue to add carbon emissions to the atmosphere at close to 10 GtC (gigatons of carbon) per year — or, if you measure the CO2 emitted instead of the carbon burned, by more than 3.67 GtCO2 per year. (GtC and GtCO2 are two ways of measuring the same thing. GtC measures the amount of carbon burned. GtCO2 measures the CO2 it becomes after being burned.)

With Trump in office, the rate will surely increase. First, he is determined to encourage exploitation and extraction of U.S. fossil fuels to the greatest extent possible. Any fuel extracted will be burned. Second, U.S. abandonment of "carbon restraint" will encourage the same behavior by other energy-poor countries like India. Third, world leadership, both moral and practical, in the fight against climate change will pass from the U.S. to either Europe, China, or both.

In which case, fourth, the U.S. will be come a pariah among nations, whether the rest of the world drowns itself or saves itself in the climate decade ahead.

Unless, of course, he pushes people too far and they "Easter Island" his regime instead.

There's always a choice, and we make it every day. Just sayin'.

(A version of this piece appeared at Down With Tyranny. GP article archive here.)