CARBON REDUCTION
Tar sands
Presumably this was not what climate cam-
paigners had in mind by attacking the relative
carbon intensity of tar sands production.
It may be that the climate threat from tar
sands has been over-stated. Peak oilers have
long argued that despite the size of the
resource, the tar sands could never be pro-
duced quickly enough to compensate for
declining production of conventional oil.
Others, such as Jackie Forest, an author of the
IHS CERA report, believe it would be “really
pushing it” to ramp up tar sands production to
6.3 million barrels a day by 2035 – which is
barely a tenth of what’s needed to replace the
predicted decline from conventional wells.
If that’s what happens, rising emissions
from slow-growing tar sands production
would be outweighed by falling emissions
from fast-depleting conventional oil, even
without CCS.
But now it seems the tar sands may not only
fail to fill the gap, but actually make it wider.
A recent paper by Myles Allen, head of cli-
mate dynamics at the Department of Physics
at Oxford University, suggests the need for a
radical new climate policy approach, one Conventional oil production is already unable to match demand
which would render exploitation of non-con-
ventional oils foolish not only in terms of of limiting warming to 2
o
C. The trillionth the fewer barrels will be available to humanity
emissions, but also the long-term fuel supply. tonne must be our last, he says. The new cap before we have to stop consuming oil
Current policy focuses exclusively on would encourage policies to cut emissions altogether. If tar sands fuels emit 20% more
reducing the atmospheric concentration of sooner rather than later, because later cuts than conventional, for every five barrels of tar
CO
2
by progressive cuts in annual emissions. would have to be steeper and inevitably sands we consume, we could have consumed
The EU, for example has a target to cut annu- more expensive to achieve. This would six conventional barrels.
al emissions by 20% by 2020, or 30% if other concentrate minds, and reduce politicians’ For coal-to-liquids fuels, such as those
countries also impose stringent targets. But room to fudge if short-term targets, such as produced in South Africa, the ratio is even
Allen’s work shows that this fixation with the those for 2020, are missed. worse: for every barrel of CTL, we deny
annual rate of emissions may be misplaced. “The response would not be to give up in ourselves two conventional barrels.
His modelling shows that the relationships despair, but to say OK, now it’s going to be We can’t have the extra conventional barrels
between yearly emissions, atmospheric even more expensive to hit the long-term goal right away, of course; the only reason the tar
concentration of CO
2
, and the temperature of avoiding dangerous climate change, how sands are being developed is because the rate
response of the climate, are highly uncertain. are we going to do it?” of conventional oil production is already
The connection between cumulative emissions A trillion tonnes may sound a lot, but we unable to match demand. And, as convention-
and temperature, on the other hand, is much have already emitted over 500B tonnes (Gt), al production peaks and goes into decline,
clearer. Scientists cannot say with any confi- says Allen, leaving around 400Gt before we fewer barrels will be available each year. If we
dence what the temperature response will be have to stop emitting altogether. And that’s forego the non-conventional barrels, we can
to a given level of emissions in a given year; only counting CO
2
, not the other greenhouse have more conventional ones, but only as
they can be much more definite about the gases, so the effective limit may be very much quickly – or slowly – as conventional deple-
temperature rise that will result from the total lower. Meanwhile, estimates of the size of tion will allow.
amount of carbon dumped into the atmos- remaining conventional oil and gas resources And that presents a problem: to allow our-
phere by humanity. suggest they contain 250-500GtC – more than selves the most barrels and energy overall
“We know that what we’ve emitted so far enough to exhaust our total ration. within our trillion-tonne carbon budget, we
has led to roughly 1
o
C warming”, says Allen, So, what would it mean if world leaders have to reduce consumption now to benefit
who has served on successive Assessments of adopted the Allen approach? That might later. It’s entirely against human nature and
the IPCC, “so if we emit the same again, we sound fanciful, given the immense difficulty of market economics, but it’s exactly what we
can expect the temperature to rise roughly achieving a meaningful deal at Copenhagen, should be doing, says Allen.
2
o
C. It makes no difference to the climate but as the climate news gets ever worse, it “We need to step back and think about
what year emissions peak, what matters is that must become more likely. In that case exploit- fossil fuel resources as a whole, and the centu-
we limit the total amount of carbon that enters ing the tar sands would not expand the total ry as a whole, and ask whether policies are
the atmosphere.” oil available to us, but reduce it. sensible in that light.”
This insight has led Allen to propose a hard That’s because, under the Allen approach, So who’s afraid of the tar sands now? I am.
ceiling for cumulative emissions of 1T tonnes each barrel of tar sands fuel consumes more of Exploiting them today could condemn us to
of carbon (1TtC, equal to 3.67Tt CO
2
), to go our total carbon budget than a conventional even greater energy shortage in future, when
alongside annual targets, as a much surer way barrel. So the more we expand the tar sands, we may be desperate for every last drop.
26 February 2010 ❘ Sustainable Business
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