A new study from The Proceedings of the National Academy of Sciences has reaffirmed that human fingerprints are all over climate change warming the Earth's atmosphere (or the troposphere where Earth weather takes place), and also found that the same greenhouse gasses we emit from burning fossil fuels are also cooling the upper atmosphere—a phenomenon that we do not know too much about. The findings reveal that satellites (increased drag), the ozone layer, and the weather on Earth will all be affected negatively in some way.
The atmosphere has four layers. We live in the troposphere, extending upward six miles above sea level. This level contains eighty percent of the atmosphere's mass but minimal volume. The next layer up is the stratosphere which extends for 31 miles, followed by the mesosphere at 53 miles, followed by the thermosphere, approximately 300 miles to 600 miles above the Earth's surface. Beyond the thermosphere is space. The further up from the surface, the less dense it becomes.
In the thinner air aloft, most of the heat re-emitted by carbon dioxide does not bump into other molecules. It escapes to space.Combined with the greater trapping of heat at lower levels, the result is a rapid cooling of the surrounding atmosphere.
According to Yale 360, the satellite data found that between 2002 and 2019, the mesosphere and thermosphere cooled by 3.1 Fahrenheit, and is likely, later this century, to cool a whopping 13.5 Fahrenheit which is five times faster than what the Earth will experience, on the ground.
This interest arises because the cooling of the upper air also causes it to contract. The sky is falling — literally.
The depth of the stratosphere has diminished by about 1 percent, or 1,300 feet, since 1980, according to an analysis of NASA data by Petr Pisoft, an atmospheric physicist at Charles University in Prague. Above the stratosphere, Mlynczak found that the mesosphere and lower thermosphere contracted by almost 4,400 feet between 2002 and 2019. Part of this shrinking was due to a short-term decline in solar activity that has since ended, but 1,120 feet of it was due to cooling caused by the extra CO2, he calculates.
The 1987 Montreal Protocol aimed to heal the annual holes by eliminating those emissions. But it is now clear that another factor is undermining this effort: stratospheric cooling.
Ozone destruction operates in overdrive in polar stratospheric clouds, which only form at very low temperatures, particularly over polar regions in winter. But the cooler stratosphere has meant more occasions when such clouds can form. While the ozone layer over the Antarctic is slowly reforming as CFCs disappear, the Arctic is proving different, says Peter von der Gathen of the Alfred Wegener Institute for Polar and Marine Research in Potsdam, Germany. In the Arctic, the cooling is worsening ozone loss. Von der Gathen says the reason for this difference is not clear.
In 2020 The Arctic experienced its first recorded ozone hole.
Chemistry is not the only issue. Atmospheric physicists are also growing concerned that cooling could change air movements aloft in ways that impinge on weather and climate at ground level. One of the most turbulent of these phenomena is known as sudden stratospheric warming. Westerly winds in the stratosphere periodically reverse, resulting in big temperatures swings during which parts of the stratosphere can warm by as much as 90 degrees F (50 degrees C) in a couple of days.
This is typically accompanied by a rapid sinking of air that pushes onto the Atlantic jet stream at the top of the troposphere. The jet stream, which drives weather systems widely across the Northern Hemisphere, begins to snake. This disturbance can cause a variety of extreme weather, from persistent intense rains to summer droughts and “blocking highs” that can cause weeks of intense cold winter weather from eastern North America to Europe and parts of Asia.
This much is already known. In the past 20 years, weather forecasters have included such stratospheric influences in their models. This has significantly improved the accuracy of their long-range forecasts, according to the Met Office, a U.K. government forecasting agency.
Yale 360 makes the critical point that our satellites are reaching the end of their lives. For example, "Of six NASA satellites on the case, one failed in December, another was decommissioned in March, and three more are set to shut down soon." No new satellites are in the pipeline.
Meanwhile, back on Earth, radiative forcing is accelerating. Fundamentally, climate forcing is similar to the CO2 measured at Mauna Loa, Hawaii.
The CO2 concentration has steadily increased since the Great Acceleration starting in the 1950s, and recently broke a record-recorded high of 425 ppm.
Radiative forcing includes all greenhouse gases, and NOAA recently found that the forcing is at 523 ppm in 2022. The difference is a significant development for global heating and one phenomenon the public knows little to nothing about.
Because we seek an index that is accurate, only direct forcing from these gases has been included. Model-dependent feedbacks and adjustments, for example, due to induced changes in water vapor, atmospheric circulation, and stratospheric ozone depletion, are not included. Other spatially heterogeneous, short-lived, climate forcing agents, such as aerosols, clouds and tropospheric ozone, are highly variable and have uncertain global magnitudes and also are not included here to maintain accuracy.
Increases in the abundance of atmospheric greenhouse gases since the industrial revolution are mainly the result of human activity and are largely responsible for the observed increases in global temperature [IPCC 2021]. Because climate feedbacks and future projections have large model uncertainties that overwhelm the uncertainties in greenhouse gas measurements, we present here an observationally based index that is proportional to the change in the direct warming influence since the onset of the industrial revolution (also known as climate forcing) supplied from these gases. This index is based on the observed amounts of long-lived greenhouse gases in the atmosphere and contains little uncertainty.
The Intergovernmental Panel on Climate Change (IPCC) defines climate forcing as “An externally imposed perturbation in the radiative energy budget of the Earth climate system, e.g. through changes in solar radiation, changes in the Earth albedo, or changes in atmospheric gases and aerosol particles.” Thus, climate forcing is a “change” in the status quo, forcing changes in the climate. IPCC takes the pre-industrial era (chosen as the year 1750) as the baseline, although some argue that 1800 is more representative (see https://gml.noaa.gov/ccgg/ghgpower/). The perturbation to direct climate forcing (also termed “radiative forcing”) that has the largest magnitude and the smallest scientific uncertainty is the forcing related to changes in the atmospheric global abundance of long-lived, well mixed, greenhouse gases, in particular, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and halogenated compounds (mainly CFCs).
Measured global atmospheric abundances of greenhouse gases are used to calculate changes in direct radiative forcing beginning in 1979 when NOAA's global air sampling network expanded significantly. The change in annual average total direct radiative forcing by all the long-lived greenhouse gases since the pre-industrial era is also used to define the NOAA Annual Greenhouse Gas Index (AGGI), which was introduced in 2006 based on measurements through 2004 [Hofmann et al., 2006a] and is updated annually.
One other mention before signing off. The Montreal Protocol was a global effort to reduce the ozone hole caused by HFC (refrigerants). The healing of Antarctica's ozone layer was recently identified as having slowed the melting of the Arctic's sea ice.
Carbon Brief writes:
Many of the chemicals banned under the agreement are powerful greenhouse gases and, by limiting their emissions, the Montreal Protocol has already averted around 0.5C of global warming.
The study, published in the Proceedings of the National Academy of Sciences, finds that the Montreal Protocol had averted more than half a million square kilometres of Arctic summer sea ice loss by 2020 by limiting warming in the region.
The future of the Arctic is still uncertain, but many experts expect the first “ice free” summer around the middle of the century. The authors find that the Montreal Protocol is already delaying this moment by around 15 years. They add that, by 2050, this landmark treaty will have averted 0.88C of Arctic warming. (The Arctic has warmed more rapidly than the global average.)
Speaking of the Arctic, ht cawfeemug: