“I’m an optimist and still believe that it is not too late, but we urgently need to develop a global economy driven by sustainable energy sources and start using CO2, as a substrate, instead of a waste product.” — Prof Ivan Janssens, recognized as a godfather of the global ecology field.
“…we are at the most dangerous moment in the development of humanity. We now have the technology to destroy the planet on which we live, but have not yet developed the ability to escape it… we only have one planet, and we need to work together to protect it.” — Professor Stephen Hawking yesterday in The Guardian.
The pathway for preventing catastrophic climate change just got a whole hell of a lot narrower.
For according to new, conservative estimates in a scientific study led by Dr. Thomas Crowther, increasing soil respiration alone is about to add between 0.45 and 0.71 parts per million of CO2 to the atmosphere every year between now and 2050.
(Thomas Crowther explains why rapidly reducing human greenhouse gas emissions is so important. Namely, you want to do everything you can to avoid a runaway into a hothouse environment that essentially occurs over just one Century. Video source: Netherlands Institute of Ecology.)
What this means is that even if all of human fossil fuel emissions stop, the Earth environment, from this single source, will generate about the same carbon emission as all of the world’s fossil fuel industry did during the middle of the 20th Century. And that, if human emissions do not stop, then the pace of global warming of the oceans, ice sheets, and atmosphere is set to accelerate in a runaway warming event over the next 85 years.
Global Warming Activates Soil Respiration Which Produces More CO2
This happens because as the world warms, carbon is baked out of previously inactive soils through a process known as respiration. As a basic explanation, micro-organisms called heterotrophs consume carbon in the soil and produce carbon dioxide as a bi-product. Warmth is required to fuel this process. And large sections of the world that were previously too cold to support large scale respiration and CO2 production by heterotrophs and other organisms are now warming up. The result is that places like Siberian Russia, Northern Europe, Canada, and Alaska are about to contribute a whole hell of a lot more CO2 (and methane) to the atmosphere than they did during the 20th Century.
When initial warming caused by fossil fuel burning pumps more carbon out of the global environment, we call this an amplifying feedback. It’s a critical climate tipping point when the global carbon system in the natural environment starts to run away from us.
Sadly, soil respiration is just one potential feedback mechanism that can produce added greenhouse gasses as the Earth warms. Warming oceans take in less carbon and are capable of producing their own carbon sources as they acidify and as methane seeps proliferate. Forests that burn due to heat and drought produce their own carbon sources. But increasing soil respiration, which has also been called the compost bomb, represents what is probably one of the most immediate and likely large sources of carbon feedback.
(A new study finds that warming of 1 to 2 C by 2050 will increase soil respiration. The result is that between 30 and 55 billion tons of additional CO2 is likely to hit the Earth’s atmosphere over the next 35 years. Image source: Nature.)
And it is also worth noting that the study categorizes its own findings as conservative estimates. That the world could, as an outside risk, see as much as four times the amount of carbon feedback (or as much as 2.7 ppm of CO2 per year) coming from soil if respiration is more efficient and wide-ranging than expected. If a larger portion of the surface soil carbon in newly warmed regions becomes a part of the climate system as microbes activate.
Amplifying Feedbacks Starting to Happen Now
The study notes that it is most likely that about 0.45 parts per million of CO2 per year will be leached from mostly northern soils from the period of 2016 to 2050 under 1 C worth of global warming during the period. To this point, it’s worth noting that the world has already warmed by more than 1 C above preindustrial levels. So this amount of carbon feedback can already be considered locked in. The study finds that if the world continues to warm to 2 C by 2050 — which is likely to happen — then an average of around 0.71 parts per million of CO2 will be leached out of soils by respiration every year through 2050.
(When soils lose carbon, it ends up in the atmosphere. According to a new study, soils around the world are starting to pump carbon dioxide into the atmosphere. This is caused by increased soil respiration as the Earth warms. Over the next 35 years, the amount of carbon dioxide being pumped out by the world’s soils is expected to dramatically increase. How much is determined by how warm the world becomes over the next 35 years. Image source: Nature.)
The upshot of this study is that amplifying carbon feedbacks from the Earth environment are probably starting to happen on a large scale now. And we may be seeing some evidence for this effect during 2016 as rates of atmospheric carbon dioxide accumulation are hitting above 3 parts per million per year for the second year in a row even as global rates of human emissions plateaued.
Beyond the Point of No Return
What this means is that the stakes for cutting human carbon emissions to zero as swiftly as possible just got a whole hell of a lot higher. If we fail to do this, we will easily be on track for 5-7 C or worse warming by the end of this Century. And this level of warming happening so soon and over so short a timeframe is an event that few, if any, current human civilizations are likely to survive. Furthermore, if we are to avoid terribly harmful warming over longer periods, we must not only rapidly transition to renewable energy sources. We must also somehow learn to pull carbon, on net, out of the atmosphere in rather high volumes.
“This study is very important, because the response of soil carbon stocks to the ongoing warming, is one of the largest sources of uncertainty in our climate models. I’m an optimist and still believe that it is not too late, but we urgently need to develop a global economy driven by sustainable energy sources and start using CO2, as a substrate, instead of a waste product. If this happens by 2050, then we can avoid warming above 2C. If not, we will reach a point of no return and will probably exceed 5C.”
In other words, even the optimists at this time think that we are on the cusp of runaway catastrophic global warming. That the time to urgently act is now.
Hat tip to TodaysGuestIs
Hat tip to Cate
Hat tip to Colorado Bob
Hat tip to Wili