In the modern day, the Earth’s surface is 0.8 centigrade hotter than it used to be. This is because it is having difficulty radiating the sun’s heat back into space after it has arrived. Carbon dioxide has a specific interaction with ‘infrared radiation’, a physics synonym for ‘heat energy’. When infrared radiation hits a carbon dioxide molecule it is absorbed and the energy it contains causes the molecule to vibrate. Eventually the energy is emitted again as infrared radiation into its surroundings. This emitted infrared radiation will be absorbed by another carbon dioxide molecule if it hits one. The process of absorption, emission, absorption means that heat in the atmosphere is effectively stored by atmospheric carbon dioxide. Now that there are 400 parts per million (compared to 315 in 1960 and around 250 in 1800) there are more carbon dioxide molecules storing heat in this way than there were before.
Methane is a greenhouse gas. It absorbs infrared radiation and releases it later, like carbon dioxide. However, it absorbs up 22 times more energy than carbon dioxide over 100 years before it breaks down into carbon dioxide, trapping a lot more heat over a short time period.
Since the end of the last ice age, around 17,000 years ago, organic matter has accumulated in the soils of northern hemisphere that lie within the Arctic Circle. Pine needles have fallen on ground that spends all of the year frozen. In the Arctic Ocean, dying microorganisms have sunk and hit an ocean floor that spends all of the year at sub zero temperatures. This organic matter decays very slowly as, below zero, bacteria and fungi don’t operate very quickly. Over this 17,000 year period, a deep layer that is part frozen water and part fossilised organic material has built up. Scientists call it methane hydrate as the organic matter can be released from its icy cage as methane, should the ice melt. Warmer, longer summers and warmer, shorter winters are causing permafrost in both the ocean and land to melt and methane is being released.
In Earth’s history, there have been about five mass extinctions of species, the last one being 65 million years ago. It is thought that a huge volcano, called a flood basalt – where a huge plume of magma from the core – surfaced, melting through the crust and forming an ocean of lava in what is now modern day Siberia. This lava flow is huge, covering most of Siberia. It is called the Siberian Traps by geologists, and you can see it if you have a digger that can take you down to the bedrock there. In case you were worried, it doesn’t look like there are any more coming our way soon!
It is thought that the eruption hit first coal seams, as it melted though the crust, and then hit permafrost methane hydrates on the surface. This released huge volumes of carbon dioxide and methane over a (geologically) small time period of a few hundred thousand years. At this mass extinction event, an estimated 75% of all species went extinct including the dinosaurs. The primary culprit being the greenhouse effect of all the suddenly released carbon dioxide and methane causing the Earth’s average temperature to rise too quickly for organisms to evolve to cope with the changing climate.
The situation of climate change induced melting of permafrost in the Arctic is analogous to the last mass extinction event in this regard, a sudden release of carbon dioxide and methane from methane hydrates. Methane is already being recorded as well above normal. The picture above shows atmospheric methane levels above the (normal) average of 1750 parts per billion with red areas being at 1950 or more parts per billion. It was made with data collected in January this year.
How much time do we have before we’re experiencing a mass extinction? Actually, arguably, we are already within one. It is estimated that around 73,000 species are going extinct every year. The background rate of extinction on earth a million years ago is estimated to be around 100 to 1000 species per year. While the current rate is not solely to do with climate change, as it is also due to habitat loss and environmental degradation through human activity, atmospheric methane levels could lead to even more rapid change in climate than we are now seeing.
Estimated volumes of methane trapped in permafrost are around 1000 billion tonnes. To put that in context, humanity has released approximately 500 billion tonnes of carbon dioxide in the last 160 years – think all cars and all industry. David Shindell and Gavin Schmidt suggest that a real-world disaster scenario would be an instantaneous release of about 10 billion tonnes of methane into the atmosphere.
Although such a release seems unlikely to occur this year, we have 30 years of warming before we know the full effects of carbon dioxide released by today’s machines and industries. This is due to lag in the system; heat accumulation takes around this long before we feel it. I can only ask: How many more years will we pollute the atmosphere with carbon dioxide and how many more years will permafrost continue to melt? It doesn’t seem like we’ll have to wait too long before a 10 billion tonne release of methane from the 1000 billion tonne store.
This is a land rights issue moving forward. If we are fighting for our right to access the life-giving thing that is the soil, what state will it be in when we get it?
It seems odd to point out that an extinction event on Earth would be bad, but here’s a couple of points: firstly, our health relies on our eating a variety of foods containing complex nutrients. Whilst we could live on synthesised fungus slime if there were no bees to pollinate elder trees, we would certainly be grotesquely unwell. Secondly, our atmosphere is maintained largely by the forests and (somewhat surprisingly) the coral reefs of the Earth. They are the primary photosynthesisers capable of producing oxygen in quantities matching the levels required by the respiration of all living things. Simply put, if they were damaged sufficiently we would lose a stable oxygen level on Earth.
We can look after the land in non-destructive ways. From permaculture principles to far eastern food forests with species densities resembling natural forest, Allan Savory’s bizarre animal husbandry techniques in deserts (check him out!) and even biodynamics, we have proof this is possible. The personal chance to be doing some of these things is one reason we fight for access to the land.
However, all will be to naught if we burn yet more carbon and further heat the atmosphere. We have little chance of using plants to sequester the carbon already overloading the atmosphere if it is already too hot and dry for them to seed. There is some hope that by using diverse crops we could collectively reduce the carbon content the atmosphere and feed all of us. However, there is a point of no return with climate change. The prospect of a 10 billion tonne release of methane in the not so distant future is it. Finally it.
In my vision of the future where the commoner is reunited with the land stolen from under her feet, I worry she will be unable to sustain herself and community from it.
I guess my conclusion is mixed. Whilst we have the knowledge to save the biosphere for our own benefit, what comes first? Access to the land or fighting for it to be preserved in some form useful to us in the future?