NASA Claims Proof That Greenhouse Gases Drive Temperature

On April 2, CBS News posted an item on their website claiming NASA now has ‘proof’ greenhouse gases drive our temperature.

The article states in part:

It may come as a surprise, given the extensive body of evidence connecting humans to climate change, that directly observed proof of the human impact on the climate had still eluded science. That is, until now.

In a first-of-its-kind study, NASA has calculated the individual driving forces of recent climate change through direct satellite observations. And consistent with what climate models have shown for decades, greenhouse gases and suspended pollution particles in the atmosphere, called aerosols, from the burning of fossil fuels are responsible for the lion’s share of modern warming.

In other words, NASA has proven what is driving climate change through direct observations — a gold standard in scientific research. 

“I think most people would be surprised that we hadn’t yet closed this little gap in our long list of evidence supporting anthropogenic [human-caused] climate change,” says Brian Soden, co-author of the study and professor of Atmospheric Sciences at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science.

By now it’s common knowledge that the rapid warming of the past century is not natural. Rather, it is a result of the build-up of heat-trapping greenhouse gases like carbon dioxide (CO2) and methane, much of it from the burning of fossil fuels. 

The science behind why the Earth is warming

When sunlight enters the atmosphere some of it is reflected back to space without heating the Earth. The rest is absorbed by the Earth’s surface and atmosphere and re-radiated as heat. Some of this heat escapes back into space, but the rest of the heat is trapped by specific molecules like CO2, methane, and water vapor. Simply, the more greenhouse gases the atmosphere has, the more heat is trapped and the more the temperature goes up.

Since the mid-1800s, CO2 in the atmosphere has increased from 280 parts per million to 415 parts per million — a 50% increase — and it is now the highest it has been in at least 3 million years. Carbon dioxide in the atmosphere is increasing at a pace 100 times faster than it naturally should. 

At the same time, suspended pollution particles, called aerosols, cool the atmosphere by blocking sunlight. This unintentional side effect of the Industrial Revolution has proven useful in masking some greenhouse warming. 

While these particles were effective at helping counteract some of the global warming in the mid to late 20th century, their impact is diminishing, because since the 1980s pollution has been gradually clearing up. While this is great news for health, it is unmasking additional warming in the system.

Together, the change in heat absorbed in our atmosphere because of changes in greenhouse gases and aerosols is called “radiative forcing.” These changes in radiative forcing throw off Earth’s energy balance. That’s because, in order for Earth’s average temperatures to remain steady, the “energy-in” from the sun must be equalized by the “energy-out” from Earth into space. 

When those numbers are equal the Earth maintains balance. But when greenhouse gases build-up, the energy going out is less than the energy entering the Earth system, which heats up our oceans and atmosphere, creating an imbalance in the Earth’s energy budget.

What NASA has done in this study is to calculate, or quantify, the individual forcings measured from specialized satellite observations to determine how much each component warms or cools the atmosphere. To no one’s surprise, what they have found is that the radiative forces, which computer models have indicated for decades were warming the Earth, match the changes they measure in observations.

New insight from NASA

Gavin Schmidt, the director of NASA Goddard Institute for Space Studies, says science has long had an overwhelming amount of indirect evidence of the factors warming the Earth. The predicted energy imbalance illustrated by decades’ worth of computer models has become apparent for all of humanity to see, from disappearing glaciers to more extreme weather disasters to warming oceans. 

“We have long had good evidence that the predicted energy imbalance was real because of the increases in ocean heat content. That is a very powerful confirmation that the models were predicting warming for the right reasons,” Schmidt explains. He says scientists have also had direct evidence that changes in greenhouse gases have been affecting the transfer and absorption of heat in the atmosphere, but only in localized settings, not a comprehensive evaluation.

Soden adds that science does have solid observational evidence that CO2 has increased over the last century due to the burning of greenhouse gases and that laboratory measurements confirm that CO2 absorbs heat, which theoretically should cause the planet to warm at roughly the rate observed over the last century. However, Soden says that observing the trapping of heat from space is actually quite challenging. This new research solves that challenge.

“This is the first calculation of the total radiative forcing of Earth using global observations, accounting for the effects of aerosols and greenhouse gases,” said Ryan Kramer, first author on the paper and a researcher at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “It’s direct evidence that human activities are causing changes to Earth’s energy budget.”

Specifically, this study has been able to calculate solid numbers for the changes in heat trapped in the Earth system from the individual contributors that influence heat transfer, like radiation, clouds, and water vapor, for the period 2003-2019.

The researchers did that by analyzing satellite observations and applying what they call “radiative kernels” to disentangle the various components controlling the transfer, absorption, and emission of heat inside the Earth system and what is sent back out into space.

Up to this point, satellite observations of Earth’s radiation budget had only measured the sum total of radiation changes, not the individual components.

All emphasis added.

Note the repeated references to computer models, and note that nowhere in the article are these claimed ‘direct observations’ explained. We are just expected to believe all this on blind faith.

If this had appeared the day before, you might have considered it an April Fool joke, but sadly, these people are deadly serious.

The CBS article is here.

There is a link in the article to the study mentioned, and I quote from it here:

Changes in atmospheric composition, such as increasing greenhouse gases, cause an initial radiative imbalance to the climate system, quantified as the instantaneous radiative forcing. This fundamental metric has not been directly observed globally and previous estimates have come from models. In part, this is because current space‐based instruments cannot distinguish the instantaneous radiative forcing from the climate’s radiative response. We apply radiative kernels to satellite observations to disentangle these components and find all‐sky instantaneous radiative forcing has increased 0.53±0.11 W/m² from 2003 through 2018, accounting for positive trends in the total planetary radiative imbalance.

This increase has been due to a combination of rising concentrations of well‐mixed greenhouse gases and recent reductions in aerosol emissions. These results highlight distinct fingerprints of anthropogenic activity in Earth’s changing energy budget, which we find observations can detect within 4 years.

While there are well‐established observational records of greenhouse gas concentrations and surface temperatures, there is not yet a global measure of the radiative forcing, in part because current satellite observations of Earth’s radiation only measure the sum total of radiation changes that occur. We use the radiative kernel technique to isolate radiative forcing from total radiative changes and find it has increased from 2003 through 2018, accounting for nearly all of the long‐term growth in the total top‐of‐atmosphere radiation imbalance during this period.

We confirm that rising greenhouse gas concentrations account for most of the increases in the radiative forcing, along with reductions in reflective aerosols. This serves as direct evidence that anthropogenic activity has affected Earth’s energy budget in the recent past.

All emphasis added.

Notice again there is no description of what these claimed direct observations actually are, and notice again the repeated reference to calculations. The claim that these calculations ‘serve as direct evidence’ is contentious at best.

The study can be seen here: agupubs.onlinelibrary

There was a similar study in 2010 published in Nature, and I quote from it here:

In principle, CO2 forcing can be predicted from knowledge of the atmospheric state assuming exact spectroscopy and accurate radiative transfer. Forcing can then be estimated using radiative transfer calculations with atmospheric temperature, the concentrations of radiatively active constituents including water vapor, O3, CH4, N2O, and less prominent well­-mixed greenhouse gases, and changes in CO2.

However, experimental validation of this forcing is needed outside the laboratory because CO2 spectroscopy is an area of active research. Furthermore, the fast radiative­ transfer algorithms that drive regional and global climate models approximate spectroscopic absorption line-­by-­line calculations with errors of about 0.6Wm−2, an amount comparable to the forcing by anthropogenic CH4 and N2O.

Specialized atmospheric observations at experimental sites in the mid­latitude continental Southern Great Plains (SGP) and the Arctic marine North Slope of Alaska (NSA) sites by the US Department of Energy Atmospheric Radiation Measurement (ARM) program produce the integrated data sets required for an independent diagnosis of the surface radiative effects of CO2.

We used spectroscopic measurements from the Atmospheric Emitted Radiance Interferometer (AERI) instrument and atmospheric state data at these two sites to test whether the impact of rising CO2 on downwelling longwave radiation can be rigorously detected.

However, AERI spectral measurements and trends are sensitive to many different components of the atmospheric state. To interpret these measurements and attribute specific signals to rising CO2 requires an accurate radiative ­transfer model that reproduces these spectra on the basis of an independent assessment of the state of the atmosphere. The model must capture instantaneous signals and long-term trends in the spectra to determine the effects of CO2on diurnal to decadal timescales.

We used the Line-­by-­Line Radiative Transfer Model (LBLRTM), which is continuously compared against other line-­by-­line models and observations.

All emphasis added.

The 2010 study can be seen here: escholarship.org

We can see that in this study also, no explanation of the claimed direct observations of CO2 forcing is present, and again we see repeated reference to calculations, estimates, and computer models.

To me, this is NOT proof of the greenhouse effect, or of carbon dioxide driving the temperature. Computer models can be tuned to produce any desired outcome. That is not proof.

All I see is proof of a continuing effort to mislead the public into believing human activity is causing massive harm to the planet.

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