Accelerating growth of carbon dioxide in the atmosphere
People may not have thought that growth in carbon dioxide (CO₂) levels in the atmosphere would accelerate, when pledges were made in 2015 at the Paris Agreement to take efforts to keep the temperature rise under 1.5°C compared to preindustrial.
Yet, on January 21, 2019, hourly average CO₂ levels well above 414 ppm were recorded at Mauna Loa, Hawaii, the highest levels since such measurements started. A daily average level of 413.86 ppm was recorded on January 22, 2019.
A recent Met Office forecast expects monthly averages to reach a level of 414.7 ppm in May 2019. The forecast expects annual average CO₂ levels at Mauna Loa to be 2.75 ppm higher in 2019 than in 2018. That figure is virtually on the trendline depicted below.
The trend in above image is calculated with NOAA 1959-2017 growth data, with an estimate for 2018 calculated by Sam Carana with NOAA January 2017-November 2018 data (orange dot), and with this Met Office forecast used for 2019 (purple dot).
Strong CO₂ growth is forecast for 2019, due to a number of factors including rising emissions, the added impact of El Niño and less uptake of carbon dioxide by ecosystems. A recent study warns that global warming will enhance both the amplitude and the frequency of eastern Pacific El Niño events and associated extreme weather events. Another recent study warns that, while the terrestrial biosphere now absorbs some 25% of CO₂ emissions by people, the rate of land carbon uptake is likely to fall with reduced soil moisture levels in a warmer world. Furthermore, forest fires will increase as temperatures rise, as soils get more dry and as winds increase in strength, resulting in further increases of CO₂ emissions.
The warming impact of CO₂ can be expected to increase over the next ten years, the more so since the warming impact of CO₂ reaches a peak ten years after emission. In conclusion, CO₂ can cause a global temperature rise of 0.5°C over the next ten years.
La Niña has kept much heat in oceans in 2018. Not surprisingly, 2018 was the hottest year for our oceans since global records began in 1958.
As an indication how much heat is contained in the North Atlantic, very high sea surface temperatures did show up recently off the coast of North America, with anomalies on January 23, 2019, as high as 12.6°C or 22.6°F (compared to 1981-2011, green circle on the image on the right).
That day, sea surface temperatures near Svalbard were as high as 18.3°C or 64.9° (green circle, image right). The Gulf Stream carries ocean heat to the Arctic Ocean and it can take a couple of months for this heat to reach the Arctic Ocean and contribute to melting of the sea ice.
So, Arctic sea ice is expected to be invaded by ocean heat from below in 2019, while El Niño will cause high temperatures over the Arctic, melting the sea ice from above.
As the temperature difference between the North Pole and the Equator narrows, the jet stream becomes wavier, allowing more heat to enter the Arctic. Furthermore, rivers that end in North America and Siberia can be expected to carry much warm water into the Arctic Ocean. With sea ice at a low, it won’t be able to act as a buffer to absorb heat for long.
The joint impact of all this is terrifying. Ocean heat may reach sediments at the seafloor of the Arctic Ocean and destabilize hydrates, resulting in eruptions of huge amounts of methane. This alone can cause a global temperature rise of 1.1°C in a matter of years.
A lot of this has not been accounted for by the IPCC, i.e. the recent increases in CO₂ emissions, increases in methane releases, increases in further emissions such as nitrous oxide and black carbon, albedo changes due to decline in the snow and ice cover and associated changes such as jet stream changes, more permafrost melting and stronger impacts of future El Niño events.
The image on the right shows the joint impact of the warming elements that threaten to eventuate over the next few years and that could result in a rapid 10°C or 18°F global temperature rise by 2026 or even earlier. Keep in mind that global biodiversity will have collapsed once temperatures have risen by 5°C.
The situation is dire and calls for comprehensive and effective action, as described at the Climate Plan.
• Faster CO₂ rise expected in 2019
• Increased variability of eastern Pacific El Niño under greenhouse warming, by Wenju Cai et al.
• El Niño events will intensify under global warming, by Yoo-Geun Ham
• Large influence of soil moisture on long-term terrestrial carbon uptake, by Julia Green et al.
• 2018 Continues Record Global Ocean Warming, by Lijing Cheng et al.
• Co-extinctions annihilate planetary life during extreme environmental change, by Giovanni Strona and Corey Bradshaw
• Climate Plan