In a few short months, world delegates will descend on Paris to debate over an acceptable framework on energy policies for their respective countries, one designed to hold global temperatures to a 2C degree increase over preindustrial levels. If this feels like a familiar film, it's because we have been there before. The last 20 years of the conference have seen mostly failed attempts at binding agreements, with the biggest polluters walking away without accountable commitments. However, given last year's historic announcement by the U.S. and China to join the European Union in limiting green house gas emissions, this could be a new deal; and a lot is riding on it.
But are we queuing up the wrong film? To be blunt, debating over whether emissions should peak in 2030 to undefined levels is a little bit like passengers on the Titanic debating over bathing suits. To begin with, a 2C degrees target is an arbitrary goal: the Earth doesn't know round decimals. It is the result of political negotiations, which have more to do with economic concerns than realistic consequences on the natural world. Our planet is already 0.8C degree warmer, and the transformations have been far-reaching and exponential.
Temperature increases have shown to disrupt air and ocean currents affecting the world's hydrological cycles and weather patterns, not to speak of sea level rise. But it can be decades before emissions evenly spread into the atmosphere; in other words, some of the warming we are experiencing today may result from emissions that were released in the 1980's. The truth is, we have no quantifiable way of knowing how to hold temperatures to a 2C degree rise. Just like a freight train's momentum is not measured by speed alone, setting goals to stabilize the Earth's temperatures in such a short term is misleading at best, and potentially dangerous.
We can land a rover on Mars, and transmit images from interstellar space but when it comes to environmental science, much remains as nebulous today as it was a century ago when scientists first speculated about the relationship of CO2 emissions to the Earth's temperature. Invested though we are in sophisticated land and satellite measurements, we are only beginning to scratch the surface on systemic changes and their feedback mechanisms.
To make matters worse, the Earth behaves in a non-linear fashion making accurate modeling even more challenging. The only thing we know is that air and ocean temperatures are rising; and the relationship of cause and effect is well understood. Central to it are anthropogenic activities, specifically the increase in green house gases associated with the burning of fossil fuels.
In other words, we can identify the cause (emissions), but we are not entirely clear on the symptoms (the plethora of changes). A temperature target is neither realistic, nor necessarily relevant. Increasingly, scientists are discovering new positive feedbacks: if the ocean warms, the ice around it melts faster; if the ice melt, water columns get affected by the cold influence of melting ice and so on. But the magnitude of these feedbacks has proven to be mostly underestimated.
Last year, NASA released the fruit of 10 years worth of studies of the West Antarctic glaciers. The findings sent a chill through the scientific community: deep warm currents driven down by cold surface water (resulting from higher ice melt pouring into the ocean) has been eating away at land-based glacier ice from below the floating ice shelves that hug them. What's more, given the down slopping of the terrain from the grounding line as it extends for hundreds of miles inland below the glacier, NASA deemed this phenomenon "unstoppable"-- a language mostly avoided among scientists (for the obvious vulnerability it creates should they later be proven wrong).
The melting of these glaciers directly contributes to ocean rise. In fact it is predicted that global levels would rise four and perhaps thirteen feet from this event alone over the next one to two centuries (this on top of the IPCC's projection of up to four feet by the end of this century). Similar events were just recently identified in East Antarctica. The rise in global sea levels speeds the melt of ice shelves everywhere, precipitating the glaciers' pour into the ocean. It is called a feedback, and predicting when it stops is almost impossible.
At the other end of the world another feedback is threatening the plausibility of stabilizing temperatures to a 2C degree rise. 5.3 million years ago, much of the northern Arctic was densely covered in spruce and pine forests. Since that time, temperature cycles have alternatively led to global sea levels rise or retreat. The more recent ice ages have trapped all that organic matter into the frozen ground, or below the ocean, as it converted into methane gas. The atmosphere presently holds about five Gigatons of methane. Off the Siberian Arctic shelf alone are an estimated 1,000 to 5,000 Gigatons of trapped methane, a green house gas eighty four times more potent than carbon dioxide during the first twenty years of its release.
Due to feedback loops, thawing and methane release may prove exponential and irreversible. An accelerated rate of methane release could throw the Earth's atmosphere into a spiral that would triple the 2C degrees increase by the end of the century. Scientists believe that high levels of methane released 252 million years ago were responsible for the Great Permian Extinction event that nearly wiped out all life on Earth.
According to James Hansen in a paper recently published by the Journal of Atmospheric Chemistry and Physics, it is the concentration of greenhouse gases that we should be focused on, and not temperature. CO2 levels have recently exceeded the symbolic mark of 400 parts per million, a level not reached in at least 800,000 years and possibly 5 million years. And they keep surging up, at rates of up to 2.9 ppm per year. Feedback loops increasingly look like they could neutralize the effects hoped for by a 2C degrees stabilization. It is imperative that we focus on carbon negative efforts on top of reductions, effective immediately.
The goal of the conference is noble: to set achievable targets and get everyone to the table. But the method is dangerous. In the hope of reaching multi lateral agreements, the scientific community has set the bar too low, exposing the Achilles heal of the conference. A negotiator worth his or her paycheck operates on the premise of wiggle room. Realistically, that option has long since been taken off the table -- read 50 years ago. Ineffectual targets happen when politics muddles up science.
Sadly, pitting scientists against political negotiators is like throwing a mouse in a bag of snakes; and expect a fair outcome. It is time to state loudly what most scientists quietly believe: a 2C degree limit is too little and inappropriate. Let us, instead, actively campaign to increase the target by focusing on emission levels before it is too late.