The Keeling Curve hits another new high
The atmospheric CO2 concentration at Mauna Loa Observatory on November 18, 2020 was 412.19 ppm. That is higher than at any time for at least 800,000 years. (See here for background on this graph, known as the Keeling Curve.)
WMO News Release, Nov. 23
The World Meteorological Organization (WMO) says that the industrial slowdown due to the COVID-19 pandemic has not curbed record levels of greenhouse gases which are trapping heat in the atmosphere, increasing temperatures and driving more extreme weather, ice melt, sea-level rise and ocean acidification.
The lockdown has cut emissions of many pollutants and greenhouse gases such as carbon dioxide. But any impact on CO2 concentrations — the result of cumulative past and current emissions — is in fact no bigger than the normal year to year fluctuations in the carbon cycle and the high natural variability in carbon sinks like vegetation.
Carbon dioxide levels saw another growth spurt in 2019 and the annual global average breached the significant threshold of 410 parts per million, according to the WMO. The rise has continued in 2020. Since 1990, there has been a 45% increase in total radiative forcing — the warming effect on the climate — by long-lived greenhouse gases, with CO2 accounting for four fifths of this.
WMO Secretary-General Petteri Taalas
“Carbon dioxide remains in the atmosphere for centuries and in the ocean for even longer. The last time the Earth experienced a comparable concentration of CO2 was 3-5 million years ago, when the temperature was 2-3°C warmer and sea level was 10-20 meters higher than now. But there weren’t 7.7 billion inhabitants.
“We breached the global threshold of 400 parts per million in 2015. And just four years later, we crossed 410 ppm. Such a rate of increase has never been seen in the history of our records. The lockdown-related fall in emissions is just a tiny blip on the long-term graph. We need a sustained flattening of the curve.
“The COVID-19 pandemic is not a solution for climate change. However, it does provide us with a platform for more sustained and ambitious climate action to reduce emissions to net zero through a complete transformation of our industrial, energy and transport systems.
“The needed changes are economically affordable and technically possible and would affect our everyday life only marginally. It is to be welcomed that a growing number of countries and companies have committed themselves to carbon neutrality. There is no time to lose.”
WMO Greenhouse Gas Bulletin #16, November 23, 2020:
During the most intense period of forced confinement in early 2020, daily global CO2 emissions may have been reduced by up to 17% compared to the mean level of daily CO2 emissions in 2019. As the duration and severity of the confinement measures remain unclear, it is very difficult to predict the total annual reduction in CO2 emissions for 2020; however, preliminary estimates anticipate a reduction of between 4.2% and 7.5% compared to 2019 levels.
At the global scale, an emission reduction of this magnitude will not cause atmospheric CO2 levels to decrease; they will merely increase at a slightly reduced rate, resulting in an anticipated annual atmospheric CO2 concentration that is 0.08 ppm–0.23 ppm lower than the anticipated CO2 concentration if no pandemic had occurred. This falls well within the 1 ppm natural inter-annual variability and means that in the short-term, the impact of COVID-19 confinement measures cannot be distinguished from natural year-to-year variability. …
Only when net fossil fuel emissions of CO2 approach zero will the net uptake by ecosystems and oceans start to reduce CO2 levels in the atmosphere. Even then, most of the CO2 already added to the atmosphere will remain there for several centuries, continuing to warm our climate. In addition, the Earth climate system has a lag time of several decades due to buffering of the excess heat by the oceans, so the sooner we reduce our emissions, the less likely we are to overshoot the warming threshold the world agreed to in the Paris Agreement.