Extreme UV - Fig 3, Estimation of solar EUV flux from TIMED/GUVI data (h/t Dr. Willie Soon).

Study claims: Climate Change Increasing the Risk of Space Junk Collisions

Guest essay by Eric Worrall

Before you ask, it’s not because of all the climate satellites NASA plans to launch in the next few years.

What if Space Junk and Climate Change Become the Same Problem?

Changes to the atmosphere caused by carbon dioxide emissions could increase the amount of debris that stays in orbit.

By Jonathan O’CallaghanMay 12, 2021, 12:38 p.m. ET

It’s easy to compare the space junk problem to climate change. Human activities leave too many dead satellites and fragments of machinery discarded in Earth orbit. If left unchecked, space junk could pose significant problems for future generations — rendering access to space increasingly difficult, or at worst, impossible.

Yet the two may come to be linked. Our planet’s atmosphere naturally pulls orbiting debris downward and incinerates it in the thicker lower atmosphere, but increasing carbon dioxide levels are lowering the density of the upper atmosphere, which may diminish this effect. A study presented last month at the European Conference on Space Debris says that the problem has been underestimated, and that the amount of space junk in orbit could, in a worst-case scenario, increase 50 times by 2100.

The research is “very important work,” said John Emmert, an atmospheric scientist at the U.S. Naval Research Laboratory in Washington, D.C., who has studied atmospheric density loss. However, Dr. Emmert says more research is needed to understand the severity of the problem — with the impact of the sun’s solar cycle also known to be a major factor in atmospheric density changes.

Read more: https://www.nytimes.com/2021/05/12/science/space-junk-climate-change.html

Some scientists appear to favour solar activity as the main forcing, with low solar activity associated with periods of reduced drag experienced by near Earth satellites and space junk.

Record‐low thermospheric density during the 2008 solar minimum

J. T. EmmertJ. L. LeanJ. M. Picone

We use global‐average thermospheric total mass density, derived from the drag effect on the orbits of many space objects, to study the behavior of the thermosphere during the prolonged minimum in solar activity between cycles 23 and 24. During 2007–2009 thermospheric densities at a fiducial altitude of 400 km were the lowest observed in the 43‐year database, and were anomalously low, by 10–30%, compared with climatologically expected levels. The density anomalies appear to have commenced before 2006, well before the cycle 23/24 minimum, and are larger than expected from enhanced thermospheric cooling by increasing concentrations of CO2. The height dependence of the mass density anomalies suggests that they are attributable to a combination of lower‐than‐expected exospheric temperature (−14 K) and reductions in the number density of atomic oxygen (−12%) and other species (−3%) near the base of the diffusive portion of the thermosphere.

In Earth’s thermosphere, density at a fixed geometric height is highly sensitive to variations of solar irradiance at extreme ultraviolet (EUV) wavelengths (0–120 nm). EUV and far ultraviolet (FUV) photons are the primary heat source of the thermosphere [Roble, 1995], which expands and contracts in response to temperature changes. Solar EUV irradiance increases by a factor of 2 or more from the minimum to maximum of the 11‐year solar activity cycle [Lean, 1997], driving order‐of‐magnitude increases of total mass density near 400 km [e.g., Emmert and Picone, 2010]. Cycle 23 (1996.4–2008.8, 12.4 years long) was unusually prolonged relative to prior cycles 22 (9.7 years) and 21 (10.3 years). The minimum of cycle 23/24 had the most days without sunspots since the 1933 minimum [Livingston and Penn, 2009]. In response to corresponding prolonged low levels of solar EUV irradiance during this period, the thermosphere is expected to have been unusually cool and contracted. Measurements of ion temperatures [Heelis et al., 2009] provide indirect evidence of this.

Read more: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2010GL043671

Another paper from 2018;

EUV Irradiance Inputs to Thermospheric Density Models: Open Issues and Path Forward

A. Vourlidas S. Bruinsma
First published: 16 January 2018

One of the objectives of the NASA Living With a Star Institute on “Nowcasting of Atmospheric Drag for low Earth orbit (LEO) Spacecraft” was to investigate whether and how to increase the accuracy of atmospheric drag models by improving the quality of the solar forcing inputs, namely, extreme ultraviolet (EUV) irradiance information. In this focused review, we examine the status of and issues with EUV measurements and proxies, discuss recent promising developments, and suggest a number of ways to improve the reliability, availability, and forecast accuracy of EUV measurements in the next solar cycle.

Solar variability influences human society in many ways, from long‐term climatic changes to telecommunications to the longevity of spacecraft. Of particular concern, here, are the effects of solar variability on the thermosphere (90–600 km altitude) where many spacecraft, including the International Space Station, reside. The main solar thermospheric drivers are (1) the extreme ultraviolet (EUV) radiant flux per unit area (irradiance) at wavelengths below ~200 nm and (2) intermittent solar wind inputs from coronal mass ejections (CMEs) and high‐speed streams (HSSs) (Chen et al., 2012; McGranaghan et al., 2014). 

Given we appear to be experiencing a prolonged period of abnormally low solar activity, any fluctuation in the thermosphere is more likely due to change in solar EUV emissions, rather than anthropogenic CO2. The EUV component of solar emissions is far more variable than total solar irradiance, so even a small change in solar activity can have a profound impact on the energy budget of layers of the atmosphere which are especially sensitive to EUV flux.

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May 13, 2021 10:09 am

TCI visualised:
comment image
No more to say, only, thermosphere is shrinking and:

When the thermosphere cools, it shrinks, literally decreasing the radius of Earth’s atmosphere. This shrinkage decreases aerodynamic drag on satellites in low-Earth orbit, extending their lifetimes. That’s the good news. The bad news is, it also delays the natural decay of space junk, resulting in a more cluttered environment around Earth.

The Chill of Solar Minimum

May 13, 2021 10:14 am

Wouldn’t increased average bulk temperature increase not only the volume of the gas of the atmosphere but the total number of molecules in the form of water vapor and other volatiles?

In turn, wouldn’t this mean the atmosphere expands to a greater volume, therefore affecting higher orbits than before?

I am likely wrong, but that is my first gut reaction to this.

Reply to  Douglas Deal
May 13, 2021 10:24 am

That was essentially the argument used when a ‘study’ came out , 2011 I think, claiming asteroid strikes would be more likely.

Reply to  SMC
May 14, 2021 9:16 am

The meteor impact thing was that long ago? Time flies I guess

May 13, 2021 10:14 am

Now, the real question is what’s the impact of Jupiter’s Great Red Spot on Earth’s climate change and vice versa?

Reply to  Pauleta
May 13, 2021 10:30 am

Well, Co2 makes storms more powerful. Therefore we can expect the great red spot to become more powerful. This will have an affect on asteroids in the asteroid belt, knocking them out of their orbits. The asteroids will head toward earth and some may impact and be large enough to eject significant aerosols into the atmosphere. These aerosols will block the sun, cooling the earth. This cooling effect will lower the CO2 concentration in the earth’s atmosphere, causing the great red spot to weaken again. It’s a feedback loop and it has a tipping point. Now, where is my study money from Big Green? 🙂

Reply to  SMC
May 13, 2021 11:51 am
Reply to  Pauleta
May 13, 2021 12:06 pm

That looks like too much work to fill out an application. Can’t you just cut me a check? I worked hard on that theory. 🙂

Reply to  SMC
May 13, 2021 8:00 pm

Sure thing …

Jean Meeus
Reply to  SMC
May 14, 2021 1:28 am

CO2, not Co2 (which is cobalt)!

May 13, 2021 10:19 am

As near as I can tell, they are arguing that since the thermosphere has contracted in recent years, and since CO2 concentrations have increased in recent years, that CO2 must be the cause of the thermosphere shrinking.

Tom Abbott
Reply to  MarkW
May 13, 2021 10:32 am

CO2 causes everything.

Pillage Idiot
Reply to  Tom Abbott
May 13, 2021 10:40 am

Never trust an atom, they make up everything!

Gregory Woods
Reply to  Tom Abbott
May 13, 2021 11:36 am

CO2 is the God Molecule…

Joao Martins
Reply to  Tom Abbott
May 13, 2021 12:07 pm


CO2 could cause everything.

Craig from Oz
Reply to  Joao Martins
May 13, 2021 5:55 pm

Joao posted:

CO2 could cause everything.

What Joao failed to add was that everything “could be worse than first thought” and “It may already be too late”.

Hoyt Clagwell
Reply to  Tom Abbott
May 13, 2021 2:15 pm

We know with absolute certainty that CO2 causes things to get worse. Now we just have to figure out if cooling is worse than heating.

Reply to  MarkW
May 13, 2021 2:03 pm

I read once somewhere, increasing CO2 increases the atmospheric volume and the hight of the radiant emittance of CO2 to space is increasing.
No idea if that is right.

Reply to  MarkW
May 13, 2021 3:36 pm

My right wrist and my left elbow have some pains ….I thought maybe climate change…but CO2 may be the real culprit?

Reply to  MarkW
May 13, 2021 3:55 pm

remember in AGW theory, correlation = causation, unless it is inconvenient.

May 13, 2021 10:22 am

Sounds like the study that said asteroid strikes would be more likely, only in reverse. Sounds about as plausible, too. Wish they would make up their mind.

Reply to  SMC
May 14, 2021 9:18 am

Should have read the comments before asking if anyone remembered that – apparently you do 🙂

Reply to  SMC
May 14, 2021 9:53 am

I agree; I do wish they would decide, so we can decide which way to wear our tin foil hats – shiny side in, or shiny side out.


Joseph Zorzin
May 13, 2021 10:30 am

So here’s the latest pontification from James Hansen:

The World Has Cooled Off – What’s the Significance?”


Alan Watt, Climate Denialist Level 7
Reply to  Joseph Zorzin
May 13, 2021 12:55 pm

Basically, if the temperature goes up it’s global warming. If the temperature goes down, it’s just global warming being sneaky.

However at the end there is one paragraph where Hansen is correct:

The second requirement is for technology to produce baseload dispatchable carbon-free electric power at a price below that of fossil fuels. Based on the price of nuclear fuel and the amount of material (concrete, steel, etc.) in a power plant, one technology with that potential is modern nuclear power. However, governments chose not to support the development of that technology. Instead, they chose an unlimited hidden subsidy of renewable energies via renewable portfolio standards for electricity as well as explicit subsidies of renewables. If uniform support had been provided for all clean energies, for example via clean energy portfolio standards, we would now be well on the way to stabilizing climate, and we would have a cleaner, healthier atmosphere.[6]

Our children and grandchildren will pay the price for our energy policy incompetence.

Of course, this only addresses electricity generation, which is about 20% of global energy consumption.

Reply to  Alan Watt, Climate Denialist Level 7
May 13, 2021 4:24 pm

Our children and grandchildren will pay the price for our energy policy incompetence.

Our children and grandchildren will pay the price for all our incompetence because we never bothered to teach them how to play kick the can (down the road). But don’t worry, they already think that everything is free, so they’ll keep voting for free stuff because they deserve it.

Reply to  Joseph Zorzin
May 13, 2021 3:50 pm

I knew it….Hansen wants to emphasize CH4 more….CO2 is just not getting the job done….and CH4 means a more direct attack on oil/gas industry…again the appeal for “our” children and grand children….what kind of oaf are you if you can’t do it for the children?

Reply to  Anti_griff
May 13, 2021 3:56 pm

I’d like my children and grandchildren to have a ffirst-rate economy to compete in.

Reply to  Joseph Zorzin
May 13, 2021 7:00 pm

I love this line from the post: “Global temperature is highly correlated (61.4%) with the Nino3.4 index”

Highly correlated? At 61.4%?

That’s not much more than 50%, which means “maybe or maybe not”?

Or am I missing something here?

May 13, 2021 10:35 am


Reply to  markl
May 13, 2021 6:41 pm

Space…. junk ….science

Joseph Zorzin
May 13, 2021 10:37 am

Now they’re blaming heart attacks on fracking!

“Living near fracking wells is linked to higher rate of heart attacks: Study
Middle-aged men in Pennsylvania’s fracking counties die from heart attacks at a rate 5% greater than their counterparts in New York where fracking is banned.”


gee, 5% is not very convincing

Reply to  Joseph Zorzin
May 13, 2021 11:12 am

I would love to know what the comparison in heart attack rates was for the same counties, in the years before fracking started.

Rory Forbes
Reply to  Joseph Zorzin
May 13, 2021 5:19 pm

I’m tired of people comparing statistics and then assigning cause. The question is, HOW is fracking increasing the incidence of heart attacks? What is the margin of error?

Craig from Oz
Reply to  Joseph Zorzin
May 13, 2021 5:59 pm

Is this 5% considered excess deaths?

Does the study compare other major causes of death in these two areas?

Colour me bitter, twisted and cynical, but… no. Personally I would rather be completely fracked than forced to eat soy, so there 😛

Reply to  Joseph Zorzin
May 13, 2021 6:55 pm

That’s pretty amazing considering that it hasn’t been all that long since New York banned fracking.

Or – there is no correlation at all. Take your pick.

May 13, 2021 10:40 am

Well it is true that the earth is being bombarded by stupidity from outer space…and probably caused by climate change scare and CCNow.

May 13, 2021 10:42 am

New study: Climate Change Causes Increased Madness and Psychotic Events, more study needed.

Reply to  ResourceGuy
May 13, 2021 2:05 pm

No, that’s settled 😀

Carlo, Monte
May 13, 2021 10:59 am

This “very important work” is complete nonsense, the atmosphere is 99+% N and O. Collisions determine how fast something falls out of orbit, not the magic molecule.

Reply to  Carlo, Monte
May 13, 2021 11:13 am

If CO2 causes the atmosphere to warm, wouldn’t that cause the atmosphere to expand?
They are always claiming that warming oceans are expanding.
For that matter, wouldn’t expanding oceans also cause the atmosphere to expand?

Last edited 1 month ago by MarkW
Carlo, Monte
Reply to  MarkW
May 13, 2021 2:59 pm

You’d think it should, but nothing makes sense in the climastrology house of mirrors.

May 13, 2021 11:02 am

Wouldn’t warming temperatures cause the atmosphere to expand thus increasing the reach of atmospheric drag? This what supposedly caused Skylab to re-enter the earth’s atmosphere years before it was expected to.

May 13, 2021 11:22 am

increase the amount of debris that stays in orbit.” If it stays in orbit it is not a problem, falling from is what people worry about. And why did copypaste that make all my print red?

Reply to  2hotel9
May 13, 2021 11:24 am

Bummer! It was all red when I typed it, what a gip! Though it is boldfaced, guess that is something. ;}

Reply to  2hotel9
May 13, 2021 12:04 pm

Well, inasmuch as fracking releases ground methane and its combustion products into the atmosphere, shouldn’t we do more of it to avoid spacejunkapocalyse?

Tom Abbott
Reply to  Elmerulmer
May 13, 2021 6:08 pm


That was funny! 🙂

Paul Johnson
May 13, 2021 11:38 am

This article attempts to link reduce atmospheric drag to increasing space debris, but fails to connect the dots. There is no mention of the practical effect of reduced drag. Will a typical satellite stay up an extra year or just one extra orbit? Once drag becomes non-trivial, re-entry follows quickly.
The article also fails to emphasize the things RESPONSIBLE space-faring nations (Yes, I’m looking at you, China) undertake to ensure safe and controlled de-orbit.

Joao Martins
May 13, 2021 12:12 pm

Keyword for this article:


Ron Long
May 13, 2021 12:12 pm

Eric, do you remember, or know about, the old “Journal of Irreproducible Results”? This report belongs in that kind of location. One favorite of mine from the Journal was that the cutting down of trees in western US converting it to paper, then easterners hoarding the National Geographic magazine, was causing land subsidence along the east coast. The report had fancy calculations to prove it.

Rud Istvan
Reply to  Ron Long
May 13, 2021 1:06 pm

The funniest article ever in that journal was ‘Quantum Gravity treatment of the Angels dancing on a pin problem. Is googlable.

pHil R
Reply to  Rud Istvan
May 13, 2021 7:59 pm

One I remember was that they actually proved that time does in fact run faster as you get older. if I remember correctly, there was also one about relativistic baseball.

Reply to  pHil R
May 13, 2021 10:03 pm

Time does too run faster when you get older, all old people know that!
I will certainly go look for that article, if only because I want to compare it to my own silly theory on that particular issue. Who knows, maybe I can move that essay from Satire to Science!
I’ll swop you a link:

May 13, 2021 12:40 pm

All the atmospheric layers respond differently to changes in the makeup of solar particles and wavelengths.
That is why jet stream tracks vary in their degree of meridionality in tandem with solar changes.
That results in variations in global cloudiness, changes in the amount of solar energy into the oceans and ultimately, via changes in the balance between El Ninos and La Ninas, periods of warming or cooling.
Nobel Prize nomination awaited.

May 13, 2021 12:44 pm

My first instinct is that the warming just does not have a significant impact one way or the other. I wonder why the authors of this study are going to so much trouble to waste our time. The ideal gas formula inplies that the small and insignificant effect would be to insignificantly increase junk falling out of the atmosphere because the warming would slightly expand the atmosphere.

May 13, 2021 1:15 pm

Models say the stratosphere is shrinking!
– – – – – – –

Greenhouse gas emissions are causing Earth’s stratosphere to SHRINK at a rate of 328ft per decade – and it could have devastating effects for satellite operations and navigation systems, experts warn
Researchers found that the stratosphere has been shrinking since at least 1980
They believe it may have started shrinking before this but earlier data is limited
The team predict that by 2080 the stratosphere could shrink by another 3,200ft


Stratospheric contraction caused by increasing greenhouse gasesRising emissions of anthropogenic greenhouse gases (GHG) have led to tropospheric warming and stratospheric cooling over recent decades. As a thermodynamic consequence, the troposphere has expanded and the rise of the tropopause, the boundary between the troposphere and stratosphere, has been suggested as one of the most robust fingerprints of anthropogenic climate change.

Curious George
Reply to  Cam_S
May 13, 2021 2:00 pm

“During 2007–2009 thermospheric densities at a fiducial altitude of 400 km were the lowest observed in the 43‐year database, and were anomalously low, by 10–30%, compared with climatologically expected levels.”

Climatologically expected densities were too high. Surely it is not an error of climatology. That hypothesis MUST be correct at any price!

Reply to  Cam_S
May 13, 2021 5:23 pm

It can’t possibly have started to shrink before 1980, because the world was suffering catastrophic anthropogenic cooling until ~1975.

May 13, 2021 1:26 pm

Surely 1 carbon atom plus 2 oxygen atoms- C O2 – have more mass than 2 oxygen atoms – O2 – alone ?
So, denser.

Mr. Lee
May 13, 2021 3:15 pm

This is literally a declaration that “the sky is falling” .

May 13, 2021 3:43 pm

Eric ==> Thanks for covering this — I was tempted but had other obligations today.

It is interesting that there is decreased drag in the thermosphere –I did notice that the Chinese rocket booster didn’t have any trouble burning up on re-entry.

Reply to  Kip Hansen
May 13, 2021 4:53 pm

The main driver of space junk collisions is well …more space junk.

Reply to  Stevek
May 14, 2021 7:28 am

SteveK ==> Now now, no pragmatism please.

Rory Forbes
Reply to  Kip Hansen
May 13, 2021 5:27 pm

I did notice that the Chinese rocket booster didn’t have any trouble burning up on re-entry.

That’s undoubtedly because the Chinese engineers ate more rice and drank tea.

Alan the Brit
May 14, 2021 12:32 am

“Our planet’s atmosphere naturally pulls orbiting debris downward”? Really, I always thought that was gravity’s job! Wow, this Carbon Dioxide stuff is really all-powerful, it can clearly do absolutely anything!!!!! Any chance it could slip a few million$ into my bank account to boost the pension??? Sarc! (not the bit about the $Ms though!)

Matthew Sykes
May 14, 2021 1:29 am

“increase 50 times by 2100” figures pulled straight out of a hat.

May 14, 2021 8:31 am

Does anyone remember a few years ago when a “study” said that climate change would increase meteor impacts, because it was expanding the atmosphere so we would catch more of them?

Bob Greene
May 14, 2021 2:12 pm

I really miss the numberwatch.uk site going inactive. The list of things global warming does gets more hilarious all the time and we really should keep compiling the list of junk science.

May 16, 2021 5:12 pm

All satellite lives matter.

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