(Global CO2 measurements over the past six months. Small dots – daily values. Large dots – weekly values. Blue line – smoothed trend. Image source: The Keeling Curve)
After hitting a new record high above 400 ppm during the latter weeks of May, 2013, CO2 followed seasonal trends by falling to a new record high low of around 393.5 ppm in early October. By early November of 2013, CO2 had rocketed back to 394.4 ppm and, if current trends continue, will likely touch 402 ppm or higher by May of 2014.
Over the past few years, worldwide CO2 values have risen by an average of around 2 parts per million each year. But in 2013, the trend line steepened, with values increasing by about 3 ppm between 2012 and 2013. Should the new, more rapid, pace hold through 2014, maximum CO2 values for that year will reach between 402 and 403 parts per million by late May.
In context with the known geological record, the current pace of CO2 increase is far faster than anything previously observed. Past major warming events, at most, hosted a yearly CO2 increase of around .35 ppm. The most recent rate of 2 ppm per year, on average, is about six times as fast. A yearly increase of 3 ppm is nearly eight times this total.
It’s worth considering this amazing fact: human emissions are more rapid now than anytime in the geological past. Nothing, not the PETM, not the great flood basalts of the Permian, exceeded the current rate of human burning. And those great past events, many coinciding with the worst mass extinctions, were 1/6th to 1/8th the pace of what humans are doing now. Our CO2 injection machinery is more powerful, by far, than even the most terrible forces ever produced by nature.
This screaming pace of CO2 increase is leading to a series of unprecedented and damaging climate, weather, and Earth systems changes. Changes we are just beginning to understand. At the very least, we have projected ourselves into climate territory not seen in the last 3.6 million years — the last time CO2 levels were as high as they are bound to be over the next ten years. And that’s if we are somehow able to halt global CO2 emissions soon. If human emissions continue to increase as they have over the past decades, by mid century, we could be looking at atmospheric CO2 levels not seen in the past 15 to 30 million years. By the end of this century, we could achieve an atmospheric state not seen in at least 55 million years.
A Little Heat Age Every Six Years
It is not just the scale of the change, creating levels of CO2 not seen since ages in the Earth’s deep past, it is the pace of this change which is so immense and dangerous. According to the most recent IPCC draft report, the current increase in CO2 levels is causing an increased heat forcing of .16 watts per meter squared at the top of the atmosphere every six years. By comparison, the grand solar minimum experienced during the Little Ice Age had a negative forcing of around .15 watts per meter squared. So we now have the equivalent to a Little Ice Age, but on the side of hot, being pumped into the Earth’s atmosphere every six years. And should the sun cool to another grand minimum, it would take only about six years of current human emissions to overwhelm its cooling effect.
Should we hope to see a continued progress of human civilizations this extraordinarily rapid and dangerous pace of human CO2 emissions is an issue that must be addressed immediately. We have likely already created a serious and devastating string of events that will continue to unfold and worsen over the coming decades and centuries. Some, we have already seen, but these are the earlier, more mild, outliers, the events we locked in 20, 30, 50 years ago. So the force of events 20 years, 30 years, 50 years from now will be proportionately worse.
Continued emissions and further increases, under such a scenario, is not a survivable option. If we are to continue, to have any hope for future progress, we need to halt this mad pace of emissions as soon as possible.