NASA Ignores Its Own Data on Solar Irradiance

Over the last few decades, NASA has launched numerous multimillion dollar satellites into space that measure solar radiation near the Earth.

Satellite measurements of irradiance started with the NIMBUS-7 in 1978. Then there’s the Earth Radiation Budget Satellite (ERBS) launched in 1984 and the Active Cavity Radiometer Irradiance Monitor (ACRIM) on the Upper Atmosphere Research Satellite (UARS) project launched in 1991.

Then there’s the Solar Radiation and Climate Experiment (SORCE), launched in 2003, which was then continued with the Total and Spectral Solar Irradiance Sensor (TSIS-1), deployed as part of the International Space Station (ISS), which will see its second iteration, TSIS-2, launched in May of 2025.

Previous research from these measurements showed a regular increase in solar irradiance over time, like this 2003 paper from Advances in Space Research.

Investigative Economics previously highlighted how both NASA’s more recent SORCE and POWER data sets showed a steady increase of solar irradiance over the last two decades.

But on their website dedicated to climate, NASA insists that solar radiation has declined in recent years and therefore is not a driver of growing atmospheric temperatures:

The amount of solar energy Earth receives has followed the Sun’s natural 11-year cycle of small ups and downs, with no net increase since the 1950s. Over the same period, global temperature has risen markedly. It is therefore extremely unlikely that the Sun has caused the observed global temperature warming trend over the past half-century.

While NASA has numerous satellite-based data sets to choose from, they based their analysis on the Spectral And Total Irradiance REconstructions (SATIRE)-T2 data from the Max Planck Institute for Solar System Research, a German research institution. The SATIRE data is a reconstruction of solar irradiance based on solar magnetograms—images of the sun’s surface based on magnetic waves.

But basing irradiance on magnetograms is measuring solar strength at or close to the surface of the sun. It’s not how much is received by the Earth, which is highly dependent on the orbit and angle of the Earth relative to the sun and potentially other factors. Instead of magnetograms, satellites in the Earth’s orbit would ostensibly provide a closer measure of received solar radiation.

Solar Output Variance Is Minimal

According to the University of Colorado’s Laboratory for Atmospheric and Space Physics, radiation coming from the sun varies “by only small fractions of one percent” over the course of its 11 year solar cycle, and that can potentially have an effect on climate.

But that’s minimal compared to other factors like variations in orbit and precession of the Earth which effect how much energy is received from the sun, otherwise known as the Milanković theory. Those changes can lead to a variance in insolation of 25 percent.

In 1997, the Milanković theory was the de facto theory of climate change.