Could Cosmic Rays Influence Global Warming?

Article written: 20 Mar , 2008
Updated: 26 Dec , 2015

The idea goes like this: Cosmic rays, originating from outside the Solar System, hit the Earth’s atmosphere. In doing so these highly energetic particles create microscopic aerosols. Aerosols collect in the atmosphere and act as nuclei for water droplet formation. Large-scale cloud cover can result from this microscopic interaction. Cloud cover reflects light from the Sun, therefore cooling the Earth. This “global dimming” effect could hold some answers to the global warming debate as it influences the amount of radiation entering the atmosphere. Therefore the flux of cosmic rays is highly dependent on the Sun’s magnetic field that varies over the 11-year solar cycle.

If this theory is so, some questions come to mind: Is the Sun’s changing magnetic field responsible for the amount of global cloud cover? To what degree does this influence global temperatures? Where does that leave man-made global warming? Two research groups have published their work and, perhaps unsurprisingly, have two different opinions…

I always brace myself when I mention “global warming”. I have never come across such an emotive and controversial subject. I get comments from people that support the idea that the human race and our insatiable desire for energy is the root cause of the global increases in temperature. I get anger (big, scary anger!) from people who wholeheartedly believe that we are being conned into thinking the “global warming swindle” is a money-making scheme. You just have to look at the discussions that ensued in the following climate-related stories:

But what ever our opinion, huge quantities of research spending is going into understanding all the factors involved in this worrying upward trend in average temperature.

Cue cosmic rays.

Researchers from the National Polytechnic University in the Ukraine take the view that mankind has little or no effect on global warming and that it is purely down to the flux of cosmic radiation (creating clouds). Basically, Vitaliy Rusov and colleagues run the analysis of the situation and deduce that the carbon dioxide content of the atmosphere has very little effect on global warming. Their observations suggest that global temperature increases are periodic when looking into the history of global and solar magnetic field fluctuations and the main culprit could be cosmic ray interactions with the atmosphere. Looking back over 750,000 years of palaeotemperature data (historic records of climatic temperature stored in ice cores sampled in the Northern Atlantic ice sheets), Rusov’s theory and data analysis draw the same conclusion, that global warming is periodic and intrinsically linked with the solar cycle and Earth’s magnetic field.

But how does the Sun affect the cosmic ray flux? As the Sun approaches “solar maximum” its magnetic field is at its most stressed and active state. Flares and coronal mass ejections become commonplace, as do sunspots. Sunspots are a magnetic manifestation, showing areas on the solar surface where the powerful magnetic field is up welling and interacting. It is during this period of the 11-year solar cycle that the reach of the solar magnetic field is most powerful. So powerful that galactic cosmic rays (high energy particles from supernovae etc.) will be swept from their paths by the magnetic field lines en-route to the Earth in the solar wind.

It is on this premise that the Ukrainian research is based. Cosmic ray flux incident on the Earth’s atmosphere is anti-correlated with sunspot number – less sunspots equals an increase in cosmic ray flux. And what happens when there is an increase in cosmic ray flux? There is an increase in global cloud cover. This is the Earth’s global natural heat shield. At solar minimum (when sunspots are rare) we can expect the albedo (reflectivity) of the Earth to increase, thus reducing the effect of global warming.

This is a nice bit of research, with a very elegant mechanism that could physically control the amount of solar radiation heating the atmosphere. However, there is a lot of evidence out there that suggests carbon dioxide emissions are to blame for the current upward trend of average temperature.

Prof. Terry Sloan and Prof. Sir Arnold Wolfendale from the University of Lancaster and University of Durham, UK step into the debate with the publication “Testing the proposed causal link between cosmic rays and cloud cover“. Using data from the International Satellite Cloud Climatology Project (ISCCP), the UK-based researchers set out to investigate the idea that the solar cycle has any effect on the amount of global cloud cover. They find that cloud cover varies depending on latitude, demonstrating that in some locations cloud cover/cosmic ray flux correlates in others it does not. The big conclusion from this comprehensive study states that if cosmic rays in some way influence cloud cover, at maximum the mechanism can only account for 23 percent of cloud cover change. There is no evidence to suggest that changes in the cosmic ray flux have any effect on global temperature changes.

The cosmic-ray, cloud-forming mechanism itself is even in doubt. So far, there has been little observational evidence of this phenomenon. Even looking at historical data, there has never been an accelerated increase in global temperature rise than the one we are currently observing.

So could we be clutching at straws here? Are we trying to find answers to the global warming problem when the answer is already right in front of us? Even if global warming can be amplified by natural global processes, mankind sure ain’t helping. There is a known link between carbon dioxide emission and global temperature rise whether we like it or not.

Perhaps taking action on carbon emissions is a step in the right direction while further research is carried out on some of the natural processes that can influence climate change, as for now, cosmic rays do not seem to have a significant part to play.

Original source: arXiv blog

30 Responses

  1. marcellus says

    I don’t believe in global warming. We should all do as much as we can to prevent the pollution of Mother Earth. But expecting humans to go to zero carbon imprint is a fantasy.

    The GW doomsayers can site any study they wish, but hurricanes aren’t becoming more numerous or intense, the sea level is not rising, and the latest indications are that the planet is cooling, not warming.

  2. Yael Dragwyla says

    Marcellus — could you provide data and links to document those three assertions? Just to cite one counterexample, hurricanes and killer tornadoes are in fact becoming more numerous and powerful — just count ’em per year for the last 20 years. “Belief” has little to do with it. Good date sets and adequate testing of theories and models has everything to do with it. I don’t see any of that in your post. So where did you get the data set to back up your assertions, what was it, and how was it collected?

  3. Mike barber says

    Who remembers the snow and the long cold winters of the 60’s? Who remembers the long hot summer of 76? Who remembers the freak low temperatures during the winter of 82? Who remembers the big storm of 87? Freak weather before freak weather existed? C’mon, there’s always been freak weather. Mother earth is always capable of springing surprises. There are too many comlpex variables at play here and it isn’t all caused by man!
    NIce to see another interesting theory to so called global warming!

  4. Mr. LAME says

    Could Bush and others animals Influence Global Warming?
    the answer is YES
    Could Benedict anus influence global warming ?
    could Emo Earth influence global warming ?
    cause she tired of abuses, she just only a rock goddammit!!!!!!!!!!!!!!!!!!!!!!!!

  5. Johnny Blues says

    Well, your descriptions of human reaction to the subject were accurate.

  6. Frank Lansner says

    The article says:
    “There is a known link between carbon dioxide emission and global temperature rise whether we like it or not.

    This is not true. On the contrary:
    The evidence for sun related warming is so much better prooven than the CO2 effect (!!) even though its not perfect yet.

    “Proof” of CO2-warming theory:
    around year 1900 its was prooven that adding extra CO2 was NOT able to make any contribution to warming. Absorbtion from water and CO2 already blocked radiation in the frequencies in question.
    Then 50 years later, it was prooven that CO2 could however change absorbance at lower pressure, that is, in high altitude. So IN THEORY there was a chance that CO2 could make a difference in 5 to 15 km altitudes.

    But as CO2 block most radiation in less than 50 ppm concentration this high altitude CO2 (at 3-400ppm) was still not likely to do much change.

    The PROOF: Then IPCC around 1990 said that we would see a more than 1 degree relative warming in high altitudes in the years to come. This would be the “proof”. BUT THERE IS NOT SUCH RELATIVE RAISE IN HIGH ALTITUDE TEMPERATURES. The last change for CO2 to have an effect was proven wrong in nature itself!

    AND! What if IPCC had been right??
    in 10 km high we have -60 degrees celcius. One degrees warming would mean -59 degrees celcius. As NO ONE has claimed that heat can goes down in the atmosphere (IT GOES UP!), the pressence itself of -59 degrees air in 10 km altitude should be able to melt the icecaps!!!!

    Summa: NO proof for CO2, but proof of NO CO2 effect!

    And even if the IPCC where right and we had -59 degrees in 10 km altitude NO ONE HAS EVER EXPALAINED HOW THIS SHOULD ROAST THE ICE SHEETS. You cant melt ice with ultra cold air at 10 km distance. This theory, believe it or not, is the poorest in history of mankind. An embarresment to science in many many many years to come.

    Thanks for reading.

  7. marcellus says

    There is no Global Warming. We just got eight inches of new snow. Al Gore can come and shovel my sidewalk.

  8. von Dawson's Express says

    I would love ‘Global Warming’ to be influanced from outer space and not man’s doing. I agree we should be taking a more care ie pollution, litter, recycling…

    One question I would like to pose if a chunk of ice melts in a glass of water the level does not go up much, so when a iceberg melts whats the fuss about sea level rising?

  9. liberum says

    Yael Dragwyla, I agree that “belief” has nothing to do with this, because science is not religion. But then, “global warming” is a lot of things, least of all science. But counting hurricanes and tornadoes over the last 20 years and saying there’s a lot more of them is also not science. Human life span (especially only 20 years!) is too short to be of any relevance when we talk about Earth as a planet which is over 4.5 billion years old. For example, tornadoes and the like (“freak weather”) in the US are NOT well studied, since it’s been only 500 years that we have any kind of usable data (and even then, not for all of the continent). We can hardly talk about trends and say that something is “normal” and someting is not. What’s normal for us, generation that lives now, may not have been normal to the 4th generation before us, and will probably be far from normal to our grandchildren.
    When talking about climate, humans tend to become arrogant in their belief (yes, belief!) that they’re responsible for everything and anything, and they tend to forget that nature works on much larger and longer (time-wise) scale than human civilisation.

  10. UkMan says

    GW deniers will latch onto ANY idea which removes human responsibility for Global Warming.

    The train of thought of the denier typically goes something like this:

    1. Deny GW is happening. Continue to burn fossil fuels.

    2. Admit GW is happening – but put it down to something other than human influence. Continue to burn fossil fuels.

    3. Admit GW is caused by humans – but say its too late to do anything. Continue to burn fossil fuels.

    The motivation of GW deniers usually fits into one or more of the following catagories.

    Refusal to change their own lifestyle
    Refusal to accept responsibility
    Fear of the consequences of GW
    Cynicism – automatically disbelieving
    Political prejudice

    Our children will pay the price for out selfish attitude.

  11. Nuno says

    4. Admit GW is happening but has no relevance to other climate changes…

  12. Well… the author doesn’t mention it, but there are other investigatios (see, for example,

    And UkMan first phrase goes exactly for the contrary. Most manmade GW proponents are leftish who can’t suffer the loss of paradigmas, and with it they got something to blame on capitalism… in fact, you can interchange their phraseology with any anti-occident speech of the 60’s.

    But, for the sake of scientific discussion… manmade GW proponents cry that the amount of CO2 in the atmosphere is the higher in 600 000 years. Well, then, two questions:

    1) The world rise in temperature in that epoch came before or after the increase in CO2?
    2) Anyway, who is to blame for that increase en CO2? Tourist ETs, maybe?

    C’mon, fellows, Gore and friends are just money-eager opportunists.

  13. Nuno says

    Climate is influenced by several variables. And it’s changes may not end life on Earth, but will certaly cause Mankind lots of suffering.

    Until industrialization Man cut out some areas of forest over a period of thousands of years for agriculture purposes. Other than that, We didn’t do much to disturb natural equilibrium.

    After industrialization (two centuries at most), Man started injecting all sorts of materials that were at rest in nature. We destroyed habitats and species. We are responsable for rapid erosion in some areas. We alterered the composition of the atmosfere.

    …And, for some reason (human nature?) there are a number of us that still think that we have no responsability with accelerating climate changes, present and future…

    Has my post started: There are several variables influencing climate… one of them is Man.


  14. UkMan says


    No matter how much we don’t want to change our lifestyle – we are causing global warming. Thats a fact. You’re clearly an intelligent guy – I think political prejudice is affecting your judgement.

    As I mentioned in an earlier post, the melting of the polar caps is not a natural event. Some of this ice is a million years old long enough for polar bears to adapt to live there.

    The probability that the polar cap melts 150 years after the industrial revolution is statistically highly unlikely. By how much would the Polar cap have to melt before you admitted GW was real? 50%? 80% 100%??

    Re. Your comment about CO2 levels 600,000 years ago: Nobody denies that there are other ways that CO2 levels can change – or that climate change is natural over long periods of time… but we are seeing climate changes occurring over timescales comparible to a human lifespan. Records are being broken every year where extreme weather is concerned.

    If you don’t bellieve Gore – believe the vast majority of the scientific.

  15. Nuno says

    We must struggle now to achieve an equilibrium with nature, not because we are left or right or for any other political reason.

    Oil will not last forever as won’t other materials we take for granted now, and certainly, after we run out of them, we’ll have lesser influence on nature. Most probably it won’t matter if you’re left or right winged then…

    We must do everything to understand what are the vectors that influence our living environment.

    It’s not wise to dismiss Cosmic Rays as an important influence, but, let’s face it, we can do little about them.

    It’s not wise to disimss our own contribute as an “environment changing vector” either… And maybe we can do something about that vector.

    Keep watching the skies people!
    Keep learning about the Universe!
    Keep on with curiosity!
    Keep being scientific!

    BTW: I’m NOT leftish.


  16. Robert Clarke says

    To UkMan: (“…we are causing global warming. That’s fact”) With respect, that is not fact. That is opinion. In planetary history, global temperature has risen at certain intervals. Carbon dioxide levels have FOLLOWED this temperature increase, not preceeded it in every case. I affirm that we must be better stewards of our planet, but we must also have our science right to do it.

    By the way, polar ice has disappeared numerous times before man’s existance. Gore is wrong. The IPCC is a joke and has its own motives and agenda. Those are facts.

    R. Clarke

  17. Eric says

    It’s obvious that O’Neill is a die hard lefty who is 100% certain that humans are completely responsible for the supposed “global warming”. From this article it makes sense to extrapolate that O’Neill was at the forefront during the 70’s declaring that humans were 100% responsible for the global “ice age” that was to engulf the planet within 25 years. Since both of those don’t work at the same time now it’s “climate change”. Maybe instead of giving Gore a Nobel Peace Prize for his nonsense book, the lefties should quit being hypocrites and actually practice what they preach and start reducing THEIR carbon footprint! Or is that someone else’s responsibility – reference Gore’s energy gobbling house.


  18. UkMan:
    Thanks for considering me an intelligent guy. I think that most of us here are, at least, a little above average intelligence, which is sad, of course.
    I’d like that you and the others would take a look at this publication:
    By the way, I agree that we humans are hurting our planet. Much damage is being done, and we should modify that. And maybe we are making some changes on climate, and surely on enviroment.

  19. Cosmos says

    For really good coverage of all aspects of climate change check this website :

  20. Trippy says

    I wonder if the Ukranian work managed to overcome one of the biggest flaws in Svensmark’s original work on the links between GCR’s and Global Warming – namely that he was never able to produce a mechanism to get from the aerosols formed to cloud droplets.

  21. Chris says

    Good one UkMan,

    I’d also say that maybe what *really* burns the deniers is the realisation that when it comes to AGW, the left/liberals were right all along. The denialist idiots are so irredeemably stupid that rather than admit this, they’ll repudiate the scientific consensus that forms what the IPCC is reporting, what thousands of working climate scientists around the world are saying, and what every authoritiave national scientific body on the planet tells us.

    Remember how the deniers all cheered when some goose announced there had been no warming since 1998 … er … except that Nasa’s GISS temp data tells us the five hottest years are:

    1. 2005
    Tie 1998/2007
    4. 2002
    5. 2003

    The warming trend looks pretty clear to me.

    But clutching at any straw (no matter how thin) to support their dishonest rantings I’d now expect them to start droning on with the usual FUD about how and why GISS is wrong, Hansen’s work can’t be trusted etc, ad infinitum, ad nauseum.

    I find it pretty strange that the deniers could think like that when they’ve got no robust published science that backs them up. None. Zip. Zero. Nada. Kinda creepy really.

  22. Dirk says

    We all comment because we all are right, right? So here’s the truth: we know virtually nothing about interstellar interaction and even gravity is really puzzling, so read “The electric sky’ (Scott) and “The final theory” (McCutheon) for understanding why humanity can’t be involved in our global warming. It is only plasma that rules the continuous universe.

  23. ‘…..we know virtually nothing about interstellar interaction and even gravity is really puzzling…..’

    I am puzzled now.
    Ian knows it and if he reports it to us it cannot be wrong.

    He is reporting everything the truth, the progress, the unknown and the undiscovered. A frontrunner at the edge of knowledge.

    All for our education and his monetary benefit.
    Lets pray to our high priest of technobabble.
    Thanks for the truth.
    Thanks for the insight.
    Thanks for the ingenuity

  24. Rob says

    It always amuses me that when Global Warming Alarmists are confronted with intelligent, solid debate on that the matter that they resort to their mantra of “attack the man, not the science”, as the increasing number of scientific papers are rapidly eroding the base for their nonsensical arguments. Anyone who is a sceptic of the IPCC is immediately labelled a “denier’, drawing non-too-subtle” comparisons to Holocaust deniers. What a healthy way to engage in scientific debate.

    Chris: You say that NASA’s GISS temp data tells us that the five hottest years were 1998/2007, 2002, 2003, 2005. Really? You forgot about 1934. I checked the NASA GISS site at They say that 1934 was technically the warmest year in their records, although 1934, 1998 and 2005 were essentially tied. Even the IPCC admits that supposed anthropogenic influences in GW only go back 30 years. How do you explain 1934?

    The reality is the Global Climate has always been and always will be in a state of change. Surely you do not deny the Medieval Warm Period (a time when temperatures were much warmer than they are today) or the Little Ice Age (1700s). Global temperature has never been static for any significant duration. These events prove that there are much larger forces in play in determining global climate. Man’s increases in CO2 emmisions are insignificant when compared those from oceans (by far the largest), volcanos, and the biosphere (plants, animals). The IPCC refuses to adequately account for natural causes of global warming. It is simply ludicrous to believe that anthropogenic causes are soley or largely to blame.

    As for your claim that there is no science backing up the belief that anthropogenic factors are insignificant to climate change in the grand scheme of things – you’re joking, right? The National Post has an excellent set of articles describing the works of various well-respected scientists around the world that are poking all kinds of holes in the AGW rantings.

    A must read in this collection is the article “IPCC too blinkered and corrupt to save”.
    You must also ready the report from the NIPCC – the Non Intergovernmental Panel on Climate Change. The NIPCC is a parallel panel to the IPCC formed by scientists frustratrated by the lack of proper scientific rigour exhibited by the IPCC. Their report is at
    The scientific reality is that the sun is the single greatest influencing factor on the earth’s temperature (both through direct radiation and its affect on cosmic radiation). It’s radiation levels vary in three well known cycles. Oceanographers know that the worlds oceans are by far the single greatest CO2 emitter/sink. When the oceans temp goes up, they emit more CO2 (this is not scientifically disputed). They also know that that oceans have an 800 year memory (ie. it takes about 800 years before global temperature changes are are reflected in deeper ocean temperatures). What that means is that our oceans are currently reacting to temperatures from about 1200 AD …right in the middle of the Medieval Warm Period. As a result, they are emitting a lot of CO2. Ice core studies – the same ones incorrectly interpreted by Al Gore in his film – show that throughout history global CO2 levels have lagged temperature by about 800 years.
    The IPCC is a politically corrupt organization that quite remarkably has hijacked the environmental agenda. We should be more worried about exhausting our fresh water supplies, and striving towards a clean, safe replacement for fossi fuels (as we have only about 100 years supply left of conventional oil).

  25. Aqualung says

    Just because the earth is warming up a bit at the moment does not make it man made.

    We must all do our bit to look after the environment and recycling has the effect of reducing CO2 and reducing the amount of raw ore processed.

    Certainly recycling is a big issue in the UK with households soon to be fined for not recycling their rubbish. BUT we still have the situation where businesses DO NOT, and their are no plans to make them, have to recycle anything!

    We have lots of huge high street stores throwing out cardboard, cans, tins, bottles and plastics. They ALL go into landfill without being sorted because there is no legislation to make them.

    If saving the planet was that important, don’t you think business would have to do their bit as well.

    If you look at my previous posts you will see that I believe GW is a natural phenomena. I also believe it has been hijacked by government as a money making scam. Hence the pressure on ordinary citizens to do all the work while business continues on regardless.

  26. alphonso richardson says

    Firstly, I agrer that GW is a natural procees. However, I disagree that mankind has not had an effect on the process.
    This is now an emotive subject, as opposed to a looney non-starter only a few decades ago. Consequently, of course, there will be individuals, politicians & businesses willing to make money out of people’s ingorance and fears.
    This however doesn’t mean that there is no problem.
    To stick with an ‘either – or’ stance so doggdley without real concern for facts & reasoned argument is simply not helpful. And I’m talking to BOTH sides on this – too much crap is talked on both sides of the debate.
    We all have a part to play & business don’t get involved unless legislation is levied AND enforced. there is another way – hit ’em in the pocket. Once their bottom line is affected, they soon take notice.
    Not easy or perfect, but surley better than slagging each other off & getting nowhere.

  27. Mr. R. L. Hails Sr. P. E. says

    I am an engineer, with forty years experience in power production: a score of nukes, two score fossil plants, and a decade + studying advanced energy technologies: fuel cells, solar electric, ultracapcitors, advanced ICE, and related material sciences, e.g. MMC, nanotechnologies, etc. I have read the pro and con GW debate, and find it vacuous. The central issue is this: > 90% of man’s energy is derived from the exothermic reaction of carbon, oxygen to carbon dioxide. Second place is held by nuclear power. The sum of all other sources is trivial, from a societal load viewpoint. All alternate prime energy sources have technical- cost limitations, e.g. material unit stress, energy conversion efficiencies, or rare materials; they can not, will not supplant fossil fuels, as bulk, cheap, universal, dependable technologies in this century. Therefore, if GW is lethal, and CO2 must be reduced by a large fraction, billions will be denied energy at today’s consumption levels. Most will die. Advanced nations can improve thermal efficiencies, as a secondary effect, but no earthly power can change the end condition. Mankind can not support 6+ billion people without combustion. It is the back bone of the industrial revolution, the prime demarcation between rich and marginally surviving societies. Extremely expensive energy is useless, and infuriating, to poor, starving people.
    The world wide ad hominum attacks among arrogant scientists, on GW must stop. We are not far from warfare on this issue, and you fuel the conflict. It is immoral to waste anything of value, and all societies waste. We must distribute the products of wealth, far more widely, so as to prevent strive. However, even this historically unattained condition will leave us with a Malthusian dilemma if fossil fuel combustion is dangerous to life.
    I am a denier. Call it abject fear, ratio a mort. I judge that the certitude of the GW arguments pales in relation to the inescapable consequences of the conclusion.
    I pray that I am wrong.

  28. Ric Werme says

    I first heard about this paper through a friend who sent me the BBC story at

    The article quotes Terry Sloan with “The IPCC has got it right, so we had better carry on trying to cut carbon emissions.” While I haven’t had a chance to digest this paper, I get real concerned when IPCC and right are used in the same sentence because I’ve heard too many problems about how they do science.

    There is a chance that pressure to have a sensible scientific dialog will greatly increase, at the very least, we may be entering a the best period since the Dalton Minimum to see what impact solar activity has on climate.

    While this study says the Cosmic Ray theory is wrong, Svensmark’s SKY experiment is quite interesting, and CERN’s upcoming CLOUD experiment will be moreso. Even better, perhaps, are predictions and evidence that the Sun is entering decades of reduced activity.

    The only catch is that the Dalton Minimum was not a pleasant time even before volcanic eruptions made things worse. From reports around the world about this winter (I saw a Chinese report yesterday – they’re still having major problems) and the recent downturn in global temps climatology is becoming exciting.

    I recently wrote a web page that reviews how science should be working and takes a brief look at both CO2 and
    Solar forcings. I hope it will help Ian O’Neill avoid getting “big, scary anger” when he writes on the subject.
    See “Science, Method, Climatology, and Forgetting the Basics” at

  29. Professor Saumitra Mukherjee says

    With due regards to the “Pundits” of Global warming, it can be easy to understand that activities of human are not the sole cause of global warming. Sun as well as extragalactic cosmic rays has a role to play in the thermosphere,ionosphere, atmosphere,hydrosphere biosphere and geosphere of the earth. The research is going on and I have no hesitation to say that it has already been published what role the Sun and Extra galactic Cosmic rays are playing with the Environment of the earth.

    Prof.Saumitra Mukherjee
    School of Environmental sciences
    Jawaharlal Nehru University
    New Delhi-110067

  30. How to Get Six Pack Fast says

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