[Vision2020] Realclimate.org: 100 Responses to "Keystone XL: Game over?" To Quote NASA's Hansen

[Ted Moffett]

For anyone wishing to be scientifically and factually well informed
about the climate change implications of Canadian tar sands
development, the following is required reading, a discussion of
climate, CO2 emissions and Canadian tar sands development from Raymond
T. Pierrehumbert, Louis Block Professor in Geophysical Sciences at the
University of Chicago, who earlier served on the atmospheric science
faculties of MIT and Princeton. His bio is here:
http://www.realclimate.org/index.php/archives/2004/12/raymond-t-pierrehumbert/

If you carefully follow his analysis, he implies NASA climate
scientist James Hansen's often quoted "game over" statement about
climate impacts of tar sands development is hyperbole, which is not to
say he disagrees that human impacts on climate are profound and long
lasting... Quite the contrary!

Skip down to "Keystone XL: Game Over" to pass my comments.

I participated a few months ago in a group discussion of McKibben's
recent book "Eaarth," where the claim was made that centuries long
predictions of climate change from human impacts are not
scientifically credible.  I wondered, haven't these ostensibly well
educated individuals surveyed all the scientific literature on this
issue?  It appeared not...

I continue to be amazed at how often ostensibly informed spokespeople
in the media, Internet, and journalism in general, pontificate on
climate science when it is glaringly apparent they have not conducted
the comprehensive scientific research that pontificating should be
based upon.

Pierrehumbert's analysis given below indicates thousands of years of
impacts on Earth's climate from human sourced CO2 emissions.

Also, as my research has indicated from numerous sources,
Pierrehumbert states that globally coal has the largest potential for
future atmospheric CO2 emissions of any traditional fossil fuel, to
quote:  "coal is still the 800-gigatonne gorilla at the carbon party."

Given the US has the largest coal reserves of any nation, slowing CO2
emissions from coal burning in the US should receive the same
attention as blocking the Keystone XL pipeline, in my opinion.

Pierrehumbert states as part of his conclusion to his analysis in the
paragraph at the bottom: "So the pipeline itself is really just a
skirmish in the battle to protect climate, and if the pipeline gets
built despite Bill McKibben’s dedicated army of protesters, that does
not mean in and of itself that it’s “game over” for holding warming to
2C.

Only text is pasted in...graphs and full public discussion are
available at the website link below:
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Keystone XL: Game over?

http://www.realclimate.org/index.php/archives/2011/11/keystone-xl-game-over/#more-9280

Filed under: Carbon cycle Climate Science— raypierre @ 2 November 2011

The impending Obama administration decision on the Keystone XL
Pipeline, which would tap into the Athabasca Oil Sands production of
Canada, has given rise to a vigorous grassroots opposition movement,
leading to the arrests so far of over a thousand activists. At the
very least, the protests have increased awareness of the implications
of developing the oil sands deposits. Statements about the pipeline
abound.

Jim Hansen has said that if the Athabasca Oil Sands are tapped, it’s
“essentially game over” for any hope of achieving a stable climate.
The same news article quotes Bill McKibben as saying that the pipeline
represents “the fuse to biggest carbon bomb on the planet.” Others say
the pipeline is no big deal, and that the brouhaha is sidetracking us
from thinking about bigger climate issues. David Keith, energy and
climate pundit at Calgary University, expresses that sentiment here,
and Andy Revkin says “it’s a distraction from core issues and
opportunities on energy and largely insignificant if your concern is
averting a disruptive buildup of carbon dioxide in the atmosphere”.
There’s something to be said in favor of each point of view, but on
the whole, I think Bill McKibben has the better of the argument, with
some important qualifications. Let’s do the arithmetic.

There is no shortage of environmental threats associated with the
Keystone XL pipeline. Notably, the route goes through the
environmentally sensitive Sandhills region of Nebraska, a decision
opposed even by some supporters of the pipeline. One could also keep
in mind the vast areas of Alberta that are churned up by the oil sands
mining process itself. But here I will take up only the climate impact
of the pipeline and associated oil sands exploitation. For that, it is
important to first get a feel for what constitutes an “important”
amount of carbon.

That part is relatively easy. The kind of climate we wind up with is
largely determined by the total amount of carbon we emit into the
atmosphere as CO2 in the time before we finally kick the fossil fuel
habit (by choice or by virtue of simply running out). The link between
cumulative carbon and climate was discussed at RealClimate here when
the papers on the subject first came out in Nature. A good
introduction to the work can be found in this National Research
Council report on Climate Stabilization targets, of which I was a
co-author. Here’s all you ever really need to know about CO2 emissions
and climate:

The peak warming is linearly proportional to the cumulative carbon emitted

It doesn’t matter much how rapidly the carbon is emitted

The warming you get when you stop emitting carbon is what you are
stuck with for the next thousand years

The climate recovers only slightly over the next ten thousand years

At the mid-range of IPCC climate sensitivity, a trillion tonnes
cumulative carbon gives you about 2C global mean warming above the
pre-industrial temperature.

This graph gives you an idea of what the Anthropocene climate looks
like as a function of how much carbon we emit before giving up the
fossil fuel habit, without even taking into account the possibility of
carbon cycle feedbacks leading to a release of stored terrestrial
carbon.  The graph is from the NRC report, and is based on simulations
with the U. of Victoria climate/carbon model tuned to yield the
mid-range IPCC climate sensitivity. Assuming a 50-50 chance that
climate sensitivity is at or below this value, we thus have a 50-50
chance of holding warming below 2C if cumulative emissions are held to
a trillion tonnes. Including deforestation, we have already emitted
about half that, so our whole future allowance is another 500
gigatonnes.

Proved reserves of conventional oil add up to 139 gigatonnes C (based
on data here and the conversion factor in Table 6 here, assuming an
average crude oil density of 850 kg per cubic meter). To be specific,
that’s 1200 billion barrels times .16 cubic meters per barrel times
.85 metric tonnes per cubic meter crude times .85 tonnes carbon per
tonne crude. (Some other estimates, e.g. Nehring (2009), put the
amount of ultimately recoverable oil in known reserves about 50%
higher). To the carbon in conventional petroleum reserves you can add
about 100 gigatonnes C from proved natural gas reserves, based on the
same sources as I used for oil. If one assumes that these two reserves
are so valuable and easily accessible that it’s inevitable they will
get burned, that leaves only 261 gigatonnes from all other fossil fuel
sources. How does that limit stack up against what’s in the Athabasca
oil sands deposit?

The geological literature generally puts the amount of bitumen
in-place at 1.7 trillion barrels (e.g. see the numbers and references
quoted here). That oil in-place is heavy oil, with a density close to
a metric tonne per cubic meter, so the associated carbon adds up to
about 230 gigatonnes — essentially enough to close the “game over”
gap. But oil-in-place is not the same as economically recoverable oil.
That’s a moving target, as oil prices, production prices and
technology evolve. At present, it is generally figured that only 10%
of the oil-in-place is economically recoverable. However, continued
development of in-situ production methods could bump up economically
recoverable reserves considerably. For example this working paper
(pdf) from the National Petroleum Council estimates that Steam
Assisted Gravity Drainage could recover up to 70% of oil-in-place at a
cost of below $20 per barrel.

Aside from the carbon from oil in-place, one needs to figure in the
additional carbon emissions from the energy used to extract the oil.
For in-situ extraction this increases the carbon footprint by 23% to
41% (as reviewed here ) . Currently, most of the energy used in
production comes from natural gas (hence the push for a pipeline to
pump Alaskan gas to Canada). So, we need to watch out for
double-counting here, because our “game-over” estimate already assumed
that the natural gas would be used for one thing or another. A
knock-on effect of oil sands development is that it drives up demand
for natural gas, displacing its use in electricity generation and
making it more likely coal will be burned for such purposes. And if
high natural gas prices cause oil sands producers to turn from natural
gas to coal for energy, things get even worse, because coal releases
more carbon per unit of energy produced — carbon that we have not
already counted in our “game-over” estimate.

Are the oil sands really the “biggest carbon bomb on the planet”? As a
point of reference, let’s compare its net carbon content with the
Gillette Coalfield in the Powder river basin, one of the largest coal
deposits in the world. There are 150 billion metric tons left in this
deposit, according to the USGS. How much of that is economically
recoverable depends on price and technology. The USGS estimates that
about half can be economically mined if coal fetches $60 per ton on
the market, but let’s assume that all of the Gillette coal can be
eventually recovered. Powder River coal is sub-bituminous, and
contains only 45% carbon by weight. (Don’t take that as good news,
because it has correspondingly lower energy content so you burn more
of it as compared to higher carbon coal like Anthracite; Powder River
coal is mined largely because of its low sulfur content). Thus, the
carbon in the Powder River coal amounts to 67.5 gigatonnes, far below
the carbon content of the Athabasca Oil Sands. So yes, the Keystone XL
pipeline does tap into a very big carbon bomb indeed.

But comparison of the Athabaska Oil Sands to an individual coal
deposit isn’t really fair, since there are only two major oil sands
deposits (the other being in Venezuela) while coal deposits are
widespread. Nehring (2009) estimates that world economically
recoverable coal amounts to 846 gigatonnes, based on 2005 prices and
technology. Using a mean carbon ratio of .75 (again from Table 6
here), that’s 634 gigatonnes of carbon, which all by itself is more
than enough to bring us well past “game-over.” The accessible carbon
pool in coal is sure to rise as prices increase and extraction
technology advances, but the real imponderable is how much coal
remains to be discovered. But any way you slice it, coal is still the
800-gigatonne gorilla at the carbon party.

Commentators who argue that the Keystone XL pipeline is no big deal
tend to focus on the rate at which the pipeline delivers oil to users
(and thence as CO2 to the atmosphere). To an extent, they have a
point. The pipeline would carry 500,000 barrels per day, and assuming
that we’re talking about lighter crude by the time it gets in the
pipeline that adds up to a piddling 2 gigatonnes carbon in a hundred
years (exercise: Work this out for yourself given the numbers I stated
earlier in this post). However, building Keystone XL lets the camel’s
nose in the tent. It is more than a little disingenuous to say the
carbon in the Athabasca Oil Sands mostly has to be left in the ground,
but before we’ll do this, we’ll just use a bit of it. It’s like an
alcoholic who says he’ll leave the vodka in the kitchen cupboard, but
first just take “one little sip.”

So the pipeline itself is really just a skirmish in the battle to
protect climate, and if the pipeline gets built despite Bill
McKibben’s dedicated army of protesters, that does not mean in and of
itself that it’s “game over” for holding warming to 2C. Further, if we
do hit a trillion tonnes, it may be “game-over” for holding warming to
2C (apart from praying for low climate sensitivity), but it’s not
“game-over” for avoiding the second trillion tonnes, which would bring
the likely warming up to 4C. The fight over Keystone XL may be only a
skirmish, but for those (like the fellow in this arresting photo ) who
seek to limit global warming, it is an important one. It may be too
late to halt existing oil sands projects, but the exploitation of this
carbon pool has just barely begun. If the Keystone XL pipeline is
built, it surely smooths the way for further expansions of the market
for oil sands crude. Turning down XL, in contrast, draws a line in the
oil sands, and affirms the principle that this carbon shall not pass
into the atmosphere.
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Vision2020 Post: Ted Moffett