When Goodes’ “Project Earthshine” and NASA’s CERES projects started back in the late 90’s, many scientists expected that water in warmer seas would evaporate more quickly. Creating thicker clouds, thereby reflecting more sunlight back into space. There was a common belief that the climate system would prove to have lots of “self-correcting” feedback’s.
The argument seemed logical, and it has been built into climate models since the 70’s. We imagined “greenhouse” Earth as a warm, wet, cloudy, rainy place. Much like the Amazon.
But evidence was accumulating in the paleontological record that suggested when CO2 levels were high in previous periods; there were very few clouds. That warming from CO2 would create an amplifying feedback by reducing cloudiness, instead of a dampening feedback of increasing cloudiness.
The evidence in the paleoclimate record strongly suggests that one of our basic assumptions about the Climate System was completely wrong.
The debate over this point has been one of the main sources of uncertainty in modeling just how sensitive the climate is to increasing greenhouse gas concentrations. Because clouds have a huge effect on the climate system. Just a small change in their extent or reflectivity would have more of an impact than all the greenhouse gases released by human activities.
Using the CERES and Project Earthshine data, a study published in the Proceedings of the National Academy of Sciences in July of 2021 found that it is 97.5 percent certain that changes in clouds brought about by climate change will amplify warming.
Observational evidence that cloud feedback amplifies global warming
The satellite and earthshine results support this conclusion: “Somehow, the warm ocean (Eastern Pacific) burns a hole in the clouds and lets in more sunlight,” Goode has stated. He noted that they started seeing this effect in 2014.
In 2014, a natural climate pattern in the Pacific Ocean called the Pacific Decadal Oscillation caused temperatures to rise quickly. Heat flowed into the Eastern Pacific and created the oceanic heatwave known as “The Blob” killing billions of sea creatures.
It turns out that warmer seas meant sparser low-level clouds, which let in even more sunlight, which warmed the ocean even more. The warming became a feedback loop that intensified the speed and amount of ocean warming.
Other researchers analyzing these patterns agree. One team at Princeton University managed to model the satellite data with near-perfect accuracy by adjusting the influence of clouds in their model. Their model considered the impacts of pollution, greenhouse gases, sea ice levels, and cloud response. Their conclusion:
The observed trend in Earth’s energy imbalance (TEEI), a measure of the acceleration of heat uptake by the planet, is a fundamental indicator of perturbations to climate. Satellite observations (2001–2020) reveal a significant positive globally-averaged TEEI of 0.38 ± 0.24 Wm−2decade−1, but the contributing drivers have yet to be understood.
Using climate model simulations, we show that it is exceptionally unlikely (<1% probability) that this trend can be explained by internal variability.
Instead, TEEI is achieved only upon accounting for the increase in anthropogenic radiative forcing and the associated climate response. TEEI is driven by a large decrease in reflected solar radiation and a small increase in emitted infrared radiation. This is because recent changes in forcing and feedbacks are additive in the solar spectrum, while being nearly offset by each other in the infrared. We conclude that the satellite record provides clear evidence of a human-influenced climate system.
Anthropogenic forcing and response yield observed positive trend in Earth’s energy imbalance
“This is on us,” said Shiv Priyam Raghuraman, a Ph.D. student who led the Princeton study and was not involved in the Earthshine Project. “We should be aware that we’re driving these changes.”
So, it could be about clouds. That’s where the extra heat might be coming from.
This should scare you.
Because if this feedback has started, we may not be able to do anything about it. We can make the planet “hazier” via geoengineering by injecting aerosol particulates into the atmosphere. That would make the planet more reflective and cool the atmosphere. But a lot of heat has built up in the oceans. This research indicates that as the oceans release it, they will suppress cloud formation.
We can make the planet hazier; we cannot make it cloudier. The implications of this are that climate change is going to be faster than we expected and harder to slow down via geoengineering. If we have triggered a cloud diminishment feedback by warming the oceans, then we are on the edge of the abyss.
Is there another explanation?
Dr. James Hansen at the Earth Institute, Columbia University thinks that there is.
To be clear, Dr. Hansen completely agrees that the Earth’s albedo has diminished. He completely agrees that this is causing the earth to warm up more quickly. Dr. Hansen isn’t arguing with what we have observed. He thinks that there is another explanation for it other than cloud diminishment.
Plunging sulfate aerosol emissions from industrial sources, particularly shipping, could lead global temperatures to surge well beyond the levels prescribed by the Paris Climate Agreement as soon as 2040 “unless appropriate countermeasures are taken,” Hansen wrote, together with Makiko Sato, in a monthly temperature analysis published in August 2021 by the Climate Science, Awareness and Solutions center at Columbia University’s Earth Institute.
That paper, “July Temperature Update: Faustian Payment Comes Due” is available for download here. In it Dr. Hansen argues that;
“Global temperature doesn’t change that much due to meteorological noise. The ocean is a huge heat reservoir and can burp up heat — indeed, that’s the cause of most interannual variability of global temperature. However, over the past several years the ocean has not been giving up heat — on the contrary, it is gaining heat at the fastest rate on record. Global warming is being forced.
None of the measured forcings can account for the global warming acceleration.
The growth rate of climate forcing by well-mixed greenhouse gases (GHGs) is near the 40-year mean. Solar irradiance is just beginning to rise from the recent solar minimum; it is still below the average over the last few solar cycles.
It follows that the global warming acceleration is due to the one huge climate forcing that we have chosen not to measure: the forcing caused by imposed changes of atmospheric aerosols.
Leon Simons — Director of Club of Rome Netherlands — sent a message to me several months ago describing regulations being imposed by the International Maritime Organization on sulfur emissions from ships. Some reductions were required by 2015 and stiffer restrictions were imposed globally in 2020. The reductions are imposed for the sake of human health; the World Health Organization reports that 3–4 million people per year die from outdoor air pollution.”
What he is referring to is this.
Since 2012, the EU has taken firm action to reduce the sulfur content of marine fuels through the Sulphur Directive. In 2016, the International Maritime Organization (IMO) maintained 2020 as entry-into-force date of the global 0.5% sulfur cap.
Shippers brace for new rules to cut deadly sulfur emissions (2016)
The shipping industry is among the world’s largest emitters of sulfur behind the energy industry, with the sulfur dioxide (SOx) content in heavy fuel oil up to 3,500 times higher than the latest European diesel standards for vehicles.
“One large vessel in one day can emit more sulfur dioxide than all the new cars that come onto the world’s roads in a year.”
To combat such pollution, the International Maritime Organization’s (IMO) Marine Environment Protection Committee met in London on Oct. 24–28 (2016) and decided to impose a global cap on SOx emissions starting from 2020, which would see sulfur emissions fall from the current maximum of 3.5 percent of fuel content to 0.5 percent.
In January 2020 the European Commission followed through on that ruling.
Cleaner Air in 2020: 0.5% sulfur cap for ships enters into force worldwide
From January 2020, the maximum sulphur content of marine fuels is reduced to 0.5% (down from 3.5%) globally — reducing air pollution and protecting health and the environment. Sulphur Oxide (SOx) emissions from ships’ combustion engines cause acid rain and generate fine dust that can lead to respiratory and cardiovascular diseases, as well as reduced life expectancy.
Later that year, in December 2020, this study “Beyond SOx reductions from shipping: assessing the impact of NOx and carbonaceous-particle controls on human health and climate” was published. In this study, sponsored by the EU Commission, the authors concluded that.
Historically, cargo ships have been powered by low-grade fossil fuels, which emit particles and particle-precursor vapors that impact human health and climate. We used a global chemical-transport model with online aerosol microphysics (GEOS-Chem-TOMAS) to estimate the aerosol health and climate impacts of four emission-control policies: (1) 85% reduction in sulfur oxide (SOx) emissions (Sulf); (2) 85% reduction in SOx and black carbon (BC) emissions (Sulf-BC); (3) 85% reduction in SOx, BC, and organic aerosol (OA) emissions (Sulf-BC-OA); and (4) 85% reduction in SOx, BC, OA, and nitrogen oxide (NOx) emissions (Sulf-BC-OA-NOx).
The SOx reductions reflect the 0.5% fuel-sulfur cap implemented by the International Maritime Organization (IMO) on 1 January 2020. The other reductions represent realistic estimates of future emission-control policies. We estimate that these policies could reduce fine particulate matter (PM2.5)-attributable mortalities by 13 300 (Sulf) to 38 600 (Sulf-BC-OA-NOx) mortalities per year. These changes represent 0.3% and 0.8%, respectively, of annual PM2.5-attributable mortalities from anthropogenic sources. Comparing simulations, we estimate that adding the NOx cap has the greatest health benefit.
In contrast to the health benefits, all scenarios lead to a simulated climate warming tendency. The combined aerosol direct radiative effect and cloud-albedo indirect effects (AIE) are between 27 mW m−2 (Sulf) and 41 mW m−2 (Sulf-BC-OA-NOx). These changes are about 2.1% (Sulf) to 3.2% (Sulf-BC-OA-NOx) of the total anthropogenic aerosol radiative forcing. The emission control policies examined here yield larger relative changes in the aerosol radiative forcing (2.1%–3.2%) than in health effects (0.3%–0.8%), because most shipping emissions are distant from populated regions.
Valuation of the impacts suggests that these emissions reductions could produce much larger marginal health benefits ($129–$374 billion annually) than the marginal climate costs ($12–$17 billion annually).
Which shows you that governmental agencies are already weighing “lives saved” versus “climate costs”. In this case estimating that the health benefits of not killing 3–4 million people a year was worth more than the extra warming caused by reducing the amount of sulfur dioxide in the atmosphere.
That’s what Dr. Hansen is disagreeing with. He thinks that there has been far more warming from the reduction in sulfur dioxide than the authors of this study anticipated.
Hansen makes a very good point.
Despite its name the CERES project doesn’t measure clouds. The CERES (Clouds and the Earth’s Radiant Energy System) instruments actually measure outgoing radiation; both reflected sunlight and emitted terrestrial heat radiation. Hansen states.
Specifically, the CERES data show that most of the increased imbalance since 2015 is due to an increase of absorbed solar energy, i.e., a decrease in Earth’s reflectivity. That is consistent with the expectation that the largest effect of aerosols on Earth’s radiation balance and climate is via their effect on clouds.
Such consistency is hardly a substitute for actual aerosol and cloud measurements.
It is possible to measure from space detailed microphysical information (particle size, shape, refractive index) for aerosols and cloud particles. Extraction of full information in reflected sunlight — including opacity of the aerosol layer and aerosol single-scatter reflectivity — requires observations of a given area from a wide range of scattering angles, in several spectral bands over the solar spectrum from the near-ultraviolet to the near-infrared, and with polarization of the reflected light measured to an accuracy of the order of 0.1 percent.
NASA once launched a mission with that capability, but it ended up on the floor of the Southern Ocean near Antarctica rather than in space, when satellite failed to separate from the launch vehicle. No replacement satellite was built — that’s a sad story for another time.
For now, we can only infer that Earth’s energy imbalance — which was less than or about half a watt per square meter during 1971–2015 — has approximately doubled to about 1 W/m2 since 2015. This increased energy imbalance is the cause of global warming acceleration.
We should expect the global warming rate for the quarter of a century 2015–2040 to be about double the 0.18°C/decade rate during 1970–2015 (see Fig. 2), unless appropriate countermeasures are taken.
What Hansen is saying is that albedo has two components: clouds and haze. What the Earthshine and CERES projects are measuring is a decline in the Earth’s albedo.
This could be caused by “cloud diminishment” as suggested by Goode. Or it could be caused by a reduction in haze caused by a reduction in sulfur dioxide due to the changes in diesel fuels used by the global shipping industry, which is what Hansen is arguing.
This is an important question. There are serious implications from each of these scenarios. If it’s a combination of both factors the ratio between them will be crucial. We will settle this issue over the next decade. What’s important for now is to be really clear about one thing.
Global warming has accelerated since 2014, almost doubling the rate of warming.
Things are getting worse much more quickly now.
This is what I see.
This is my analysis.
This is my “Crisis Report”.
-rc
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