Extracting and burning the tarsands would represent a carbon release on par with that of Saudi Arabia’s current oil reserves 1

Human activities have already elevated atmospheric carbon dioxide 40% above pre-industrial levels 2, causing an unequivocal increase in the heat trapping capacity of the atmosphere3. Yet, the warming to date would be thought of as modest compared to what’s in store if Obama chooses to allow the Keystone XL pipeline to be established.

Approving this pipeline moves us much faster on a path that has begun to trigger a runaway climate change.

Deep-ocean cores have recorded past atmospheric chemistry in the layers of sediments that accumulate over time. These records teach us that a global cooling began 50 million years ago4 leading to the eventual formation of Earth’s major ice sheets at the north and south poles5. Over this time, a vast reservoir of incompletely decomposed former plant life carbon has accumulated just below the surface. An Arctic tundra and shallow northern seas carbon giant sleeps, and should not be awakened.

The Arctic is more sensitive to the presence or lack of reflective snow and ice because during Arctic summers, the sun shines all day. Consequently, as snow and ice melt (or accumulate) in the Arctic, the climate warms (or cools) there about twice as much it does in the mid-latitudes (where most Americans live). This is what climatologists call polar amplification. Temperature records thus demonstrate how annual average temperatures in the far north have risen above pre-industrial levels by 2 C (3.6 F)6 while global average temperatures have increased 0.85 C (1.5 F)7.

The same deep ocean sediment cores recorded an enormous release of carbon to the atmosphere 56 million years ago. At this time, global temperatures rapidly increased to a level more than 12 C (20 F) warmer than today. We can learn from this ancient pre-history that today we need be making a rapid transition away from carbon-based energy rather than the opposite, burning extremely high carbon emitting tarsands.

As if the problem wasn’t bad enough, as the Arctic climate warms, tundra wildfires are now occurring more commonly, releasing enormous additional carbon to the atmosphere. Thus, as human activity has already triggered Arctic warming, another important amplifier is beginning to kick in, further increasing the warming via the release of carbon stored just below the surface.

If Obama enables the US in a business as usual sense, to just keep on burning fossil fuels, he is enabling the Arctic tundra to thaw that much faster and in turn continue to amplify the initial warming.

Science tells us that for a stable climate, we need to aim for atmospheric carbon at or below 350 parts per million (ppm)8. Atmospheric concentrations are already above 393 ppm. So now is the time to invest to reverse the carbon trend not to further ensure runaway climate change.

For the sake of our future, to keep climate change within reach of a manageable level, let’s urge Obama to reject the proposal to link the Keystone XL pipeline with US refineries.

Jason E. Box, PhD - climatologist