The Science of Climate Change Explained: Facts, Evidence and Proof

The Science of Climate Change Explained: Facts, Evidence and Proof

Definitive answers to the big questions.

A long but comprehensive article!

Author Julia Rosen is a journalist with a Ph.D. in geology. Her research involved studying ice cores from Greenland and Antarctica to understand past climate changes.


I liked that article. It answers nearly all of questions commonly raised by climate skeptics, and it uses language that should be approachable for most non-scientists. I will definitely try to remember this article when I run across people who have questions on the topic.


I don’t recall reading much about how this author’s notes connect with faith or a biblical perspective, but I do have some concerns about what is said.

My most important issue is about the role of the sun in warming our planet. The author seems to acknowledge that all of the heat that we enjoy comes from the sun. For sure, it is the only noteworthy source of heat that we have on an on-going, global basis. However, here is where I think she runs into difficulty - comments to the effect that solar activity has decreased since 1950, leading to the assertion that the sun couldn’t contribute to the warming that happened at the end of the 20th century. I realize that this is an assertion widely held in climate change circles, but it completely misconstrues how the sun operates.

It is true that the activity peak of Solar Cycle 19 (circ 1958) was the strongest in the last 200 years and that every solar cycle peak since has been lower. However, the fact that solar energy hasn’t increased does not mean that it hasn’t continued to add heat and drive warming. For example, if you have a large pot of cool water on the stove, you don’t have to continually increase the heat in order for it to get warmer. If you leave the stove at above average heat, the water will get warmer and warmer. In fact, you could start with the stove on high for a short period, gradually decreasing to med-high, and then medium, and you know what happens - the pot of water continues to warm. Even though the supply of heat is decreasing, it still adds heat to the system.

When I look at the record of the latest solar cycles, I see 7 consecutive solar cycle peaks above the recent historical average, all the way from 1938 right through 2002. That was the longest above average solar activity stretch that we know of. It could well have been contributing a significant portion of warming throughout that period. It is only with the most recent solar cycle peak (cric 2014) that solar activity has dropped below the recent historical average - and we had what became know as the warming hiatus.

The next solar cycle peak (expected 2025) is forecast to be another below average solar peak. This will be the first time there has been back-to-back below average solar cycles in more than 180 years.
Eureka! We have a tailor-made, natural experiment to follow. CO2 will likely continue to increase, while solar activity stays below average for another 11 years … and what will global temp do???

Note: You can follow ‘Solar Cycle Progression’ and see its history at -

No doubt there are other factors to consider - eg added heat from extreme wildfires; positive feedback (warming) from reduced snow/ice cover, as well as from past heat build-up in oceans and earth’s crust - but if the fears about existential threats are true, then the low solar activity should have almost no affect on global temp and the increasing CO2 level should drive average surface temp another 0.25 C higher by 2030. Any less warming would / should push the climate change analyzers to adjust the CO2 climate sensitivity in their modeling. Some say the CO2 climate sensitivity factor will drop by more than half of the common value used currently.

Even as that data accumulates, I’m especially interested to see how high this next solar cycle peak reaches. The early stages of this new solar cycle have been on the low side compared with previous cycles. It may be more than a coincidence that the latest global average temps are closer to those of 2013 & 2014 than they are to reaching any new highs,
… see YTD global average temps at

and the latest temp drop could eventually leave 2015-16 and 2019-20 as outlier temp spikes driven more by warm ocean surface temps, extreme wildfire heat and other natural positive feedbacks, than by CO2 ghg effect. If so, then climate change becomes something to be aware of, but not a crisis.

I know this all sounds simplistic and surely the high-paid scientists have already thought about it, but I can’t find a reasonable explanation / proof anywhere that shows why solar activity must increase in order for it to generate more warming. And if it isn’t true, then now I can see a biblical principle to apply to this work - let’s stick to the truth.

See this topic in the article:

How do we know global warming is not because of the sun or volcanoes?

There’s actually nothing in the author’s comments, or the linked articles, to explain how anyone can say that the sun’s activity must increase in order to add warming to the planet. There is a colourful graphic emphasizing the fact that the solar cycles since # 19 (circ 1958) are lower. However, as I’ve illustrated with the warming of a pot of water analogy, even when you start with high heat and reduce that heat, there is still added warming, so long as that heat is more than the system can absorb. This is very simple, demonstrable and true. I have yet to find any explanation for how/why this concept would not apply in understanding the heat from the sun.

Here’s a little deeper dive into the solar activity data - the 4 solar cycles, dating roughly 1910-1950, are credited with a strong warming at the same time. The 4 solar cycles at the end of the century, dating roughly 1965-2005, even though all slightly lower than the extra strong solar cycle peak in 1958, have essentially the same total energy input as the earlier warming period. So, why is the same amount heat responsible for strong warming at one time and have no impact (some even claim that there should have been cooling) in another time? There is no explanation or evidence, that I’ve been able to find, to make such a determination.

In most scientific endeavours there would be an effort to design an experiment to differentiate the effects of different drivers. In this case, I think we are all looking for more clear evidence of the effect of solar activity (and possible related natural amplifiers) versus CO2 level. If I was designing such an experiment, I would conduct a number of tests - increase CO2 while solar heat is kept low; increase CO2 while solar heat is increased; increase CO2 while solar heat is kept high; hold CO2 steady while solar heat is kept low; hold CO2 steady while solar heat is increased; hold CO2 steady while solar heat is kept high. Unfortunately, bench scale tests with CO2 and some artificial heat source, run the risk of missing possible natural amplifiers. So, I understand why not much is done in the lab. And in real-life, it is virtually impossible to influence these factors in a controlled manner, which leaves us watching the evidence of the natural progression, hoping to see something of significance.

Low, and behold, we have a ready made, natural experiment unfolding all around us. Whereas CO2 has been steadily increasing since mid-20th century, even slightly accelerating, and continuing to increase today, solar energy had a period of 7 consecutive above average cycles over roughly the same period, which for my thinking makes it difficult to say which one had how much effect on the warming at that time. What would be great is to have a significantly different set of CO2 and solar energy inputs and see what happens to global temp. And, voila, we are now forecasting having two back-to-back, below-average solar cycles for the first time in more than 180 years. The first of these cycles had a peak around 2014, with the second expected around 2025. These will still only be just a little below medium heat, and not all the way to historical low, so likely no snap ice-age, but should be different enough from the previous 50-60 years to provide some really worthwhile data / evidence of the true impact of solar activity and any related amplifiers.

I’d be happy to watch this with you and others over the coming years and have a proper scientific observation, discussion and interpretation discourse. Maybe we can help lead some important perspective on the climate issue. None of us wants to ignore a potential serious problem, yet I’m not comfortable with the level of fear around something that has so little solid evidence.

Maybe that’s another faith element for me. I’ve come to understand, at least a little bit, that fear is something that we are not meant to live with. It seems to me that most of what we read about climate change is how bad it could be if the worst was to happen and that worst is based on solar activity having negligible impact on global temp. If we could get better definition of the relative impacts of solar, related natural factors, and CO2, then we might be able to take a bunch of the fear out our day-to-day living and allow us to focus more on feeding the hungry, etc.

Yes, the article is wide-ranging, but the key element of solar energy vs increased CO2 ghg effect is only a choice made by presumably smart people, with no real evidence to support the claim that solar energy must increase in order to provide added warming of the planet.

If you’ve had a chance to read my other comments, then perhaps you’ll have some thoughts about how/why we can say that the same amount of 40 year heat could cause strong warming in the first half of the 20th century and then in the last half of the 20th century it has no impact, or some would say should have cause cooling if it wasn’t for added CO2 ghg effect?

Where does the author say that the sun’s activity must increase in order to add warming to the planet? It’s greenhouse gases that are warming the planet. And it’s the lower atmosphere that is warming–that wouldn’t be from the sun.

What, me worry? Climate change is already having negative effects, as the article explains. Glad you mentioned feeding the hungry, because the article also mentions that the poor are disproportionally affected by climate change.

btw, I hope to bring some high-powered help to this thread. I don’t see that BioLogos is much interested these days.

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Does anyone really think that countries like China or India are going to reduce their use of fossil fuels? Yes, I know about China’s massive program to build nuclear plants, but they are NOT going to reduce their consumption of energy resources of any kind, and that includes oil and natural gas. China will be happy to buy and use all the fuel we won’t use when Jobama shut down the Keystone pipeline.

Did you even read the article?

How do you know exactly what these countries are going to do? Actually the Climate Action Tracker rates both India and China as doing better than the U.S. in stopping global warming.

Gotta love these political posts.

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Ok, she doesn’t say it the same way I did, but she does say

‘We know that, from 1900 until the 1950s, solar irradiance increased. And studies suggest that this had a modest effect on early 20th century climate, explaining up to 10 percent of the warming that’s occurred since the late 1800s. However, in the second half of the century, when the most warming occurred, solar activity actually declined. This disparity is one of the main reasons we know that the sun is not the driving force behind climate change.’

The ‘disparity’, in her way of saying it, means that the way that the sun caused warming in the first part of the century is by a pattern of increasing activity, whereas in the second half, solar activity didn’t increase so that is one of the main reasons why the sun is not 'the driving force behind climate change.

Looking further into the reference that she bases her thoughts on it says in part

‘One of the “smoking guns” that tells us the Sun is not causing global warming … is that there has been no upward trend in the amount of the Sun’s energy reaching Earth.’

At this point, we are only quibbling over semantics. It is clear that IPCC and many others give little credit to solar activity and possible related natural factors, crediting all, or at least most, of the recent warming drive to increasing CO2 level, which in turn leads them to assign a ‘strong’ climate sensitivity to CO2, pushing climate models to project extreme warming IF CO2 levels continue to increase. It all stems from whether or not the sun and other natural factors could be responsible for a significant portion, or maybe even a majority, of the recent warming. I say that we don’t really know, but the next few years will give us much clarity on the subject. Stay tuned.

Bill J wrote: “”" The author seems to acknowledge that all of the heat that we enjoy comes from the sun. For sure, it is the only noteworthy source of heat that we have on an on-going, global basis."""

I think Earth’s 20TW of radiogenic heat flow is noteworthy. There’s also what is termed the primordial heat, that is, the energy due to the original assembly of the earth and the kinetic energy of its constituent parts.

I’m not sure what the issue is about solar irradiance, though. The recent historical variation in solar irradiance is certainly under 2%. The present CO2 atmospheric concentration is higher by over 33% than anything more recent than 800K years ago, and comparable to concentrations some 3 million years ago, when average temperature was also some 2 to 3 degrees C higher than in the modern pre-industrial era.

I tend to think that there is already sufficient clarity to be getting on with.


If the amount of heat coming in hasn’t increased then solar activity can’t explain the increase in temperature. It is that simple. What has changed, by a lot, is the amount of greenhouse gases in the atmosphere. This reduces the amount of heat leaving the Earth which causes the heat to build up.

An analogy that might help is a car engine. Let’s say we have two cars with identical engines and identical cooling systems. We set them side by side and let the engines run at 3,000 rpm for 20 minutes. You should find that both engines are at the same temperature. Now let’s change something about one of the cars. Let’s wrap its engine and radiator in insulating blankets so it can no longer radiate heat as easily. What will happen? We will see that the engine with insulating blankets will suddenly be running much hotter than the other engine. Why? Because it isn’t able to radiate out heat as efficiently. The heat output of the engine hasn’t changed, but the amount of heat it can shed to the air around it has changed. That is how the greenhouse effect works.

There are two factors here, solar input and radiative output. Solar input has not changed, but the radiative output of the Earth has changed because of an increase in greenhouse gases. When you increase greenhouse gases you trap more heat. There is no escaping this fact.


Amen. Just look at Venus.

She had to fan herself so hard her arms fell off.


(I thought the glue melted.)

The article is good, but that is hardly all there is to it. There are other questions to be asked… and answered.

Why can’t we rely on the processes which converted all the carbon dioxide to oxygen in the first place?

  1. Because this was under very different conditions such as a much higher temperature.
  2. Because it takes too long.
  3. Because those processes have been damaged and are greatly inhibited by other problems humans have created, like pollution and damage to the ozone layer.
  4. It takes more than just converting carbon dioxide to oxygen. The carbon has to be taken out of the cycle such as happened before with the creation of crude oil and natural gas.

Why can’t we do our own conversion of carbon dioxide to oxygen, and create our own crude oil faster or accelerate the natural processes?

We can. But it is going to be a lot more expensive than just taking (thieving) what is already there – making other renewable source of energy much more appealing. And we need to start doing it soon before the increase in global temperature causes runaway climate changes – assuming it is not too late already. So many of these problems are self-correcting – unfortunately this mostly will include a considerable loss of human life and well being.

I think there is a Biblical parallel here. We are like the kingdom of Judah living on borrowed time with many prophets warning that our complacency based on a trust that God will protect us is foolish.

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My question is not about whether there is a greenhouse effect, nor about whether some gasses (eg CO2, CH4, H2O) exhibit more of that greenhouse effect (via re-radiation), nor even whether a change in level of the more impactful greenhouse gasses will have a direct impact on heat retained around our planet. All of these things are true - there is a greenhouse effect; CO2 is a more impactful greenhouse gas than the more prominent O2 and N2; and increase in CO2 will add some warming to the planet. Can we just agree on these and more to the more difficult, finer point, of how much impact does that change in atmospheric CO2 content really have.

From all of my reading, the basic ‘evidence’ for the rather strong climate sensitivity assigned to CO2, stems from calculations of how much heat has accumulated since about 1950 when it is deemed that CO2 reached a pivotal threshold, less a little bit for natural positive feedbacks that were already building, less almost nothing for possible changes in cloud cover (with a footnote that we don’t really know much about this potential climate factor) and very little consideration of heating impact from the sun. Whatever was left over has been assigned as the impact of increasing CO2 level since 1950.

However, essentially dismissing solar input as a significant warming factor because it hasn’t been increasing, is not sensible and not supported by any scientific investigation. As suggested by the simple warming pot scenario, you can see that so long as an active heat source exceeds a system’s ability to handle the incoming energy, the system will warm - you can leave the heat the same, increase or even decrease the setting - all will continue to add warming so long as it is over that minimum threshold.

In the case of the sun, we have been told that the amount of energy in the first half of the 20th century was enough to cause warming and because CO2 was still relatively low and increasing relatively slowly, the warming at that time was predominantly attributed to heat from the sun plus small contributions from positive feedbacks. Interestingly, there did happen to be an overall increase in solar activity over the 41 year span (1913-1954). More importantly was the total heat input, which was above historical average and, represented as number of sunspots (a common proxy for relative solar energy), totaled 42,371. At the same time there was a significant warming of ~0.10 C/decade.

In the latter half of the 20th century, we are told that because the successive solar cycles did not display a pattern of increasing energy, the sun could not be responsible for the warming that happened at that time. Yet, solar activity over a similar 41 years span (1965-2006) was also above historical average, totaling 50,448 - significantly more than the earlier period. I suggest that the sun is therefore responsible for at least the same amount of warming as in the earlier period (likely even a little bit more), plus positive feedbacks had increased, and CO2 had become more of a factor than before. Considering the increased warming rate over that period (~0.15 C/decade), you can see that the sun and positive natural feedbacks combined would account for something in the order of 75-80% of that warming, rather than CO2 being the only (as some would say) or even dominant (as many more would say) climate driver.

Of course, that still leaves a real impact from an increasing greenhouse gas effect - something important to watch carefully and plan around, perhaps even take steps toward limiting CO2 emissions / increasing CO2 removal, but much smaller than currently used in IPCC projections and arguably not enough for a crisis level global mobilization.

I don’t know what your are reading, but the planet is already in a climate crisis.

Since solar input has not changed or has gone down then all we are left with is the amount of heat leaving the Earth.

The impact of the sun is considered just as much, if not more, than greenhouse gases. It seems that the only reason you doubt this is because they arrive at an answer you don’t like.

How is it not sensible??? It seems entirely sensible to me.

Then Sun has been warming the Earth for 4.5 billion years, plenty of time to reach near equilibrium. The tiny changes in solar output can not have the effect you are looking for.

Notice how solar output and temperature stopped following one another on the right side of the graph:


I think we need a more nuanced vocabulary about environment. It seems to me that some people will say that we have an environmental crisis when overall littering continues in spite of efforts to limit it. It is out of control and needs to be addressed. While that isn’t great, it really isn’t an existential crisis.

With the bigger anthropogenic greenhouse warming issue, we have many reports about how this could become a crisis if warming continues as IPCC and others project. Some will even declare that such warming is already inevitable, which means that the crisis is now baked into our future and life is basically over - its just a matter of when the end will come.

What I, and some others, are seeing is evidence that CO2-driven warming, while real, is not as serious of a threat as imagined via computer-generated projections, may not lead to any sort of crisis at anytime in the future and for sure does not represent a crisis at the moment.

As best I can tell, it all stems from how much warming impact is attributed to the magnitude of solar energy input and any natural related feedbacks, which would change our assessment of the impact of CO2. As you have read in my warming pot analogy, but I’m not sure you’ve really processed as yet, I wonder how the same amount of solar heat input during one 4 decade time-span can be responsible for significant warming and then have no impact at another time. The good news about this is that you and I don’t need to make any sort of final determination on this. The actual real-life data will tell us and the next few years promise to have the most differentiated comparison of solar versus CO2 as any period that we have had in the last 70 years.

For current conversation purposes, I’d be interested to hear what you have to say about my suggestion that even a reducing pattern of heat input can continue to add heat to a pot of cool water so long as it is above a balance point.

“Let your conversation be always full of grace, seasoned with salt, so that you may know how to answer everyone.” -Colossians 4:6

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