Human Extinction by 2025?

Most important metric
Kevin Trenberth et al. suggest in a recent article that Earth’s energy imbalance, defined as the absorbed solar radiation minus the net outgoing longwave radiation, is arguably the most important metric related to climate change. Of the extra heat from Earth’s energy imbalance, about 93% ends up in the ocean as increasing ocean heat content (see image below), 3% goes into melting ice, 4% goes into raising temperatures of land and melting permafrost, and less than 1% remains in the atmosphere. 
One could also argue that the most important metric related to climate change is the monthly mean surface temperatures on land, as illustrated by the image below that was created with a July 16, 2022 screenshot from NASA customized analysis plots and shows that the February 2016 (land only) anomaly from 1886-1915 was 2.94°C or 5.292°F. 
Land only anomalies are important. After all, most people live on land and humans will likely go extinct with a rise of 3°C above pre-industrial, as illustrated by the image below, from an analysis in earlier post.

Note that in the above plot, anomalies are measured versus 1886-1915, which isn’t pre-industrial. The image raises questions as to what the temperature rise would look like when using a much earlier base, and how much temperatures could rise over the next few years.  

Potential for temperature rise on land

The image below shows land only surface temperature anomalies, similar to the above image but further adjusted by almost a degree to reflect a pre-industrial base, ocean air temperatures and higher polar anomalies, as discussed at the pre-industrial page.
The image features two trends. The blue trend is based on January 1880-June 2022 land only data and shows the potential for 3°C to be crossed on land and to drive humans into extinction by 2025. The green trend is based on January 2010-June 2022 land only data and shows the potential for 5°C to be crossed on land by 2026, which will likely drive most life on land into extinction. 

A temperature rise of 3°C would likely stop all activities by humans, including their emissions, yet temperatures could keep rising.

Could
 temperatures keep rising?

In the video below, Guy McPherson discusses Abrupt, Irreversible Climate Change to Cause Planetary Extinction.

Concentrations of greenhouse gases in the atmosphere constitute yet another important metric related to climate change. Carbon dioxide at Mauna Loa in June 2022 was 420.99 ppm, a joint record high with May 2022, as illustrated by the above image. Methane and nitrous oxide concentrations are also at record high since 1750, as illustrated by the image on the right, from an earlier post

Greenhouse gas concentrations this high are likely to keep adding ocean heat for some time, causing further melting of sea ice, etc.

All these metrics are important, including Earth’s energy imbalance, concentrations of greenhouse gases in the atmosphere, and monthly land only surface temperature anomalies.

Greenhouse gases remain in the atmosphere for many years, so even if emissions by people’s activities stop now, concentrations of greenhouse gases that have a long lifetime are unlikely to fall much over the next few years, while there would be additional emissions (such as carbon monoxide) from decomposing biomass, forest fires and waste fires globally that would also make it hard for concentrations of shorter-lived methane to fall, as also discussed here.
We’re also moving into a new El Niño, as illustrated by the image on the right. The difference between the top of El Niño and the bottom of La Niña could be more than half a degree Celsius, as the NOAA image below shows. The upcoming El Niño may well coincide with a peak in sunspots in 2025, further pushing up temperatures, as also discussed in the post Cataclysmic Alignment, which also mentions a recent study that warns that the combined impact of aerosols and nitrogen fertilizers can contribute much more strongly than previously thought to the formation of cirrus clouds that contribute to global warming. 
The resulting heatwaves and fires could trigger massive blackouts and, as civilization grinds to a halt, this could cause much of the sulfate masking effect to fall away almost instantly, resulting in further acceleration of the temperature rise. 
All this looks set to contribute to keep temperatures rising for years to come, with the danger of increasing ocean temperatures to the point where there would be massive eruptions of seafloor methane that contribute to the clouds tipping point at 1200 ppm CO₂e to be crossed, which in itself would push up temperatures by a further 8°C and cause rapid extinction of most life on Earth, as this 2019 analysis and this and this more recent analyses warn.
[ from earlier post ]

The clouds tipping point could be crossed as a result of seafloor methane releases. There is potential for such releases, given the rising ocean heat and the vast amounts of methane present in vulnerable sediments at the seafloor of the Arctic Ocean, as discussed in posts such as this one. If methane concentrations would increase in line with the trend in the above mage, i.e. methane reaching 780 ppm CO₂e by 2028 using a 1-year GWP of 200, this plus a concentration of carbon dioxide of 420.99 ppm as in the image further above would suffice to cause the clouds tipping point to be crossed. When adding further forcers, this could happen even earlier.
[ click on images to enlarge ]

Altogether, the global temperature could rise by more than 18°C above pre-industrial within a few years, as also discussed at the Extinction page. Even the longer-term outlook doesn’t look promising. A 2020 analysis by Jorgen Randers et al. points out that, even if all greenhouse gas emissions by people could stop immediately and even if the temperature anomaly could fall to 0.5°C above pre-industrial, greenhouse gas levels would start rising again after 2150 and keep rising for centuries to come, while, as discussed in an earlier post, a 2016 analysis by Ganapolski et al. suggests that even moderate anthropogenic cumulative carbon dioxide emissions would cause an absence of the snow and ice cover in the next Milankovitch cycle, so there would be no buffer at the next peak in insolation, and temperatures would continue to rise, making the absence of snow and ice a permanent loss for millennia to come.

Conclusion

In an earlier post, the following question was also discussed: Could temperatures keep rising? This post concludes that surface temperatures on land could rise strongly over the next few years and drive humans into extinction as early as in 2025. Temperatures could continue to rise afterwards and drive most life on Earth into extinction soon thereafter, making it the more important to do the right thing now and help avoid the worst from happening, through comprehensive and effective action as described in the Climate Plan.

Our duty to support local people’s courts that administer local feebates 

The disregard for science and democracy by those in power has now become so apparent and appalling that we, the people, must agree that the best way forward is to institute Local People’s Courts in which randomly-chosen residents administer local feebates, as a superior form of democracy and decision-making.

Elections do allow people to participate in decisions regarding their own lives and future, but elections only give people a single choice every few years between representatives who then take decisions of importance for them. While this can be regarded as a shallow form of democracy, it is now sufficiently clear that elections effectively remove people’s participation in such decisions and deteriorate the outlook and future for people and the environment locally and globally.
Residents should participate in decisions regarding their own lives and environment by supporting Local People’s Courts that administer local feebates, with fees added to the sales price of polluting products and to rates on degraded land, and with revenue of fees used to fund support for improvements, such as through rebates on cleaner products sold locally or rebates on local rates on improved land. Local People’s Courts can best ensure that choices regarding percentages and eligibility of fees and rebates are science-based, while feebates leave the choice as to what to buy or sell to individuals.

[ image from earlier post ]
Links

• A perspective on climate change from Earth’s energy imbalance – by Kevin Trenberth et al. 

https://iopscience.iop.org/article/10.1088/2752-5295/ac6f74

• Another Record: Ocean Warming Continues through 2021 despite La Niña Conditions – by Lijing Cheng et al. 
https://link.springer.com/article/10.1007/s00376-022-1461-3

• Improved Quantification of the Rate of Ocean Warming – by Lijing Cheng et al. 

https://journals.ametsoc.org/view/journals/clim/35/14/JCLI-D-21-0895.1.xml

• NASA – GISS Surface Temperature Analysis 

• An earth system model shows self-sustained thawing of permafrost even if all man-made GHG emissions stop in 2020 – by Jorgen Randers et al.
https://www.nature.com/articles/s41598-020-75481-z

• Could temperatures keep rising?

• Critical insolation–CO2 relation for diagnosing past and future glacial inception – by Andrey Ganapolski et al. (2016)
https://www.nature.com/articles/nature16494

• NOAA – Trends in Atmospheric Carbon Dioxide – Mauna Loa, Hawaii 
https://gml.noaa.gov/ccgg/trends/graph.html

• Will COP26 in Glasgow deliver?

• Impact of interannual and multidecadal trends on methane-climate feedbacks and sensitivity – by Chin-Hsien Cheng et al.
https://www.nature.com/articles/s41467-022-31345-w

• NOAA – ENSO: Recent Evolution, Current Status and Predictions
https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

• NOAA – Monthly Temperature Anomalies Versus El Niño

• Cataclysmic Alignment 
https://arctic-news.blogspot.com/2022/06/cataclysmic-alignment.html

• Sunspots
https://arctic-news.blogspot.com/p/sunspots.html

• Methane rise is accelerating