Everyone has heard of the carbon dioxide ‘culprit’. Carbon dioxide has become the face of human-induced climate change. It is important to remember, however, that it is not the only greenhouse gas that humans release to the atmosphere, directly or indirectly. Efforts to manage greenhouse gas emissions must also consider gases such as methane and nitrous oxide from both natural and anthropogenic sources.
Methane is a less cited offender due to its much lower atmospheric concentration (1.8 parts per million versus 391 for carbon dioxide) and shorter lifespan in the atmosphere. That being said, the two gases are not equivalent in terms of their impacts. Methane is a much more efficient greenhouse gas, with 25 times more global warming potential than carbon dioxide (nitrous oxide, present in even smaller amounts, is 300 times more efficient!).
Most projections of carbon emissions focus on greenhouse gases released by humans directly. What they do not take into account is the natural feedbacks that are triggered by global warming. At the moment, humanity operates on the assumption that climate change is a reversible process. Whenever we decide to reduce our emissions and take action, the planet will be happily waiting. Unfortunately, the truth is far from it. While it may be possible (at least in theory) to turn off the industrial carbon dioxide tap, natural processes that may be initiated by even minor changes in global temperature do not have an easy ‘off’ switch.
The Arctic has been hit hard by recent warming, with sea ice at a record low and glaciers retreating at an alarming rate. A process which is rarely mentioned is the thawing of permafrost. Permafrost presents a vast reservoir of organic matter, trapped in ice for millennia. Should all this carbon be released, it would release twice the amount of carbon currently in the atmosphere. This dwarfs the emissions that humans release directly through all combined activities.
Katey Walter Anthony has received significant media attention for her research on methane emitted from northern lakes. As permafrost beneath these lakes begins to thaw, it releases methane, which becomes trapped in the ice cover. While the ice only offers a temporary barrier, it is a valuable tool for studying the nature and magnitude of these releases. Many lower latitude lakes also release methane through natural processes, such as decomposition of organic matter by microbes, however these emissions are much smaller and are not a result of human-induced climate change.
As part of her research (or for the excitement), Dr. Walter Antony ‘pops’ ice bubbles and sets the methane on fire. Take a look!
The real danger is that of runaway natural feedbacks – processes that, once initiated, cannot be stopped and continue ever faster, much like a car with no brakes rolling down a hill. And while the next few decades may signal an energy revolution for humankind, the effects even of current anthropogenic emissions lie hidden in the pipeline, and their impacts will not be fully felt for another 20 to 30 years.
While the science is dire, opportunities always await to the entrepreneurial eye. Permafrost offers a vast source of natural gas waiting to be harnessed. And while on its own, using this natural gas for energy would just perpetuate the unsustainable behaviors that drive climate change in the first place, together with innovations such as clean-burning technologies and carbon capture, there may still be hope for us yet.
Image CC Jim’s outside photos on Flickr