Carbon Dioxide Concentration Highest in 14 million years

An article published in Science finds that 420 ppm of carbon dioxide corresponds to when the Earth was as much as 9 degrees Fahrenheit warmer.

Too Little and Too Much

Robert Hunziker quotes an estimate of $200 trillion needed to achieve zero emissions by 2050. Meanwhile, the "production gap" is expected to be twice the level of fossil fuels by 2030 than what would be consistent with the 1.5 degree warming limit.

Increasing Rate of Warming

An article published in Oxford Open Climate Change called "Global warming in the pipeline" finds that the 

decline of aerosol emissions since 2010 should increase the 1970–2010 global warming rate of 0.18°C per decade to a post-2010 rate of at least 0.27°C per decade. Thus, under the present geopolitical approach to GHG emissions, global warming will exceed 1.5°C in the 2020s and 2°C before 2050.

Lead author James Hansen: 

The 1.5-degree limit is deader than a doornail. And the 2-degree limit can be rescued, only with the help of purposeful actions.

Uncharted

An article published in BioScience updates "vital signs" for the planet. There are now 20 of 35 at record extremes.

The effects of global warming are progressively more severe, and possibilities such as a worldwide societal breakdown are feasible and dangerously underexplored.

[W]e advocate for reducing resource overconsumption; reducing, reusing, and recycling waste in a more circular economy; and prioritizing human flourishing and sustainability. We emphasize climate justice and fair distribution of the costs and benefits of climate action, particularly for vulnerable communities. We call for a transformation of the global economy to prioritize human well-being and to provide for a more equitable distribution of resources. We also call to stabilize and gradually decrease the human population with gender justice through voluntary family planning and by supporting women's and girls' education and rights, which reduces fertility rates and raises the standard of living.

Missing the Present

This year is likely to be the warmest on record--exceeding the years 2016 and 2020. Berkley Earth estimates there is a 55 percent chance the temperature anomaly for 2023 will reach 1.5 degrees Celcius.

And as Émile Torres points out, this summer will be among the mildest for the rest of our lives.

In a few decades, we'll look back on 2023 as the calm before the storm, when life was still fairly normal. Our children may even remember this year with nostalgia, as a fading glimpse of a world they never got to know — one marked by relative stability rather than environmental chaos and catastrophic collapse. For all the horrors of this summer, we should perhaps take a moment to appreciate it, because this may be as good as it gets moving forward.

Climate Deaths

A study published in Energies estimates the toll from future warming.

Several studies are consistent with the "1000-ton rule," according to which a future person is killed every time 1000 tons of fossil carbon are burned (order-of-magnitude estimate). If warming reaches or exceeds 2 °C this century, mainly richer humans will be responsible for killing roughly 1 billion mainly poorer humans through anthropogenic global warming, which is comparable with involuntary or negligent manslaughter.

Hottest Month (Yes, So Far)

The Copernicus Climate Change Service announced that last month is the warmest on record by a wide margin.

July’s global average temperature of 16.95 degrees Celsius (62.51 degrees Fahrenheit) was a third of a degree Celsius (six tenths of a degree Fahrenheit) higher than the previous record set in 2019.

The month was 1.5 degrees Celsius (2.7 degrees Fahrenheit) warmer than pre-industrial times [and] 0.7 degrees Celsius (1.3 degrees Fahrenheit) hotter than the average July from 1991 to 2020.

Days in July have been hotter than previously recorded from July 2 on.

Update (September 6):  The World Meteorological Organization announced that this summer was the warmest for the Northern Hemisphere. 

Last month was not only the hottest August scientists ever recorded by far with modern equipment, it was also the second hottest month measured, behind only July 2023.

Update (October 9):  And now the record for the largest monthly anomaly.

Last month's average temperature was 0.93 degrees Celsius (1.7 degrees Fahrenheit) above the 1991-2020 average for September. That's the warmest margin above average for a month in 83 years of records kept by the European Space Agency's Copernicus Climate Change Service.

Copernicus calculated that the average temperature for September was 16.38 degrees Celsius (61.48 degrees Fahrenheit), which broke the old record set in September 2020 by a whopping half-degree Celsius (0.9 degrees Fahrenheit).

Update (November 10):  Climate Central reports that the twelve months from November 2022 to October 2023 were the warmest in recorded history. 

[A]verage global temperatures during that period were roughly 1.32º Celsius (2.4º Fahrenheit) above preindustrial averages. As a result, roughly nine out of ten humans alive experienced at least 10 days over the past 12 months during which high temperatures would have been unlikely if not for climate change.