The Version 6.1 global area-averaged temperature trend (January 1979 through January 2025)
remains at +0.15 deg/ C/decade (+0.22 C/decade over land, +0.13 C/decade over oceans). Source: Dr. Roy Spencer

So, does carbon dioxide warm the Earth, or doesn’t it? Are extreme weather events getting more frequent and severe, or aren’t they? Why is there so much confusion about these things? Today I’m going to answer a question someone posed on our website.

The questioner, who apparently lives in the United Kingdom, wrote:

Hello! I recently watched Dr Beisner being interviewed on Answers in Genesis about global warming (in a programme from a couple of years ago). He emphasised that God is sovereign and then went on to disagree with the widely held current view that global warming is due to the rise of carbon dioxide in the atmosphere. We would all agree that our climate is warming up and floods ‘ forest fires etc are becoming more common. So, if its not increased carbon dioxide – what is it that is causing the changes, please? The TV news in Britain today is saying that the world temperatures in January were the highest ever. Many thanks.

First, I don’t disagree, and hope I didn’t say anything that properly would be understood as disagreeing, that atmospheric carbon dioxide warms Earth’s surface. It does, by slowing the escape of radiant heat (infrared) from Earth to space. (This means that while it warms the surface, it cools the upper atmosphere, by the way.)

What I do disagree with is the claim that increasing atmospheric carbon dioxide has been the sole cause of global warming in the modern period. The modern warming period began at least in the early 19^th century, long before human activity raised CO2 concentration sufficiently to have contributed to it.

Thus we can be quite confident that warming can occur in the absence of raised CO2 concentration—and indeed paleotemperature data demonstrate that it has happened repeatedly, in several cycles of different lengths, throughout geologic history. That, in turn, means we cannot know that the global warming of, say, the last 20, or 40, or 60 years was driven exclusively by CO2. I think—as to many climate scientists—that CO2 (along with other greenhouse gases, particularly methane) has contributed, but that a number of other factors have done so, too.

Second, while we would all agree that the secular (start to end) trend in global average surface temperature over, say, the past 10, 20, 30, 40, 50, right up to about 250 to 300, years has been upward (a net total of about 2.16F since about 1850), before which there was a secular (start to end) cooling period from about 1250 to 1750 or 1800, all climate historians also agree that during all that period the warming has been interrupted by periods of cooling as well—just not as much cooling, usually, as warming, which yields the secular (start to end) upward trend.

But this provides another reason to reject the idea that CO2 is the sole cause of the warming—because while the warming and cooling have alternated, the rise in CO2 concentration has been quite steady since the early 19^th century. Further, during any given period shorter than, say, about 5 years, we really can’t know whether in that period we’re in the midst of warming or cooling—because that period may in fact be at the outset of one of the intermittent cooling cycles. It may, in fact, even be at the start of a long-term cooling cycle (since such cycles have happened repeatedly in the past.)

Third, most people who think we’re seeing more frequent or intense heat waves, floods, droughts, hurricanes, wildfires, etc.—extreme weather events—have been led to that conclusion because they’re looking at damage figures from them. The damage figures, though, must, at least in part, but attributable to changes in the quantity of people and property in their paths.

For instance, the same hurricane impacting a location with very little property will cause very little property damage but, impacting a location with much property, will cause more property damage. Or, if the same hurricane impacts a place with few people it will kill few people, but if it hits a place with many more people (but living at the same development level—houses and the like of the same quality and hence the same vulnerability to high winds and rain), it will cause many more deaths.

Significantly, though, the rate of human deaths from extreme weather events has declined by over 98 percent over the past hundred years—not because the extreme weather events are less common or less severe, but because the people are better protected by structures, weather forecasts warning of coming storms, and emergency services.

Now, the data show clearly that property losses from hurricanes have increased over the last hundred years or so. However, indexed (adjusted) to account for the change in amount of property in their paths, the difference in property losses turns out to be attributable entirely to the change in amount of property in their paths.

In fact, the actual hard data on frequency and intensity of extreme weather events—as distinct from property damage due to them—indicate no upward trends. (Indeed, with regard to hurricanes, there’s actually been a small but significant reduction over about the last 60 years.)

With regard particularly to wildfires, there has been no increase, on any state/provincial, national, regional, or global scale, in their frequency and size, but rather actually some decline.

Why, then, do so many people get the impression that such extreme weather events are increasing? Partly because of poor media reporting, but partly also because our means of observing them have greatly improved. Before Doppler radar, many F1, F2, and even F3 tornadoes, for instance, were never observed—we know they took place, but they weren’t observed and counted. With the adoption of Doppler radar, we now can observe tornadoes we never observed before. The growth of population in tornado-prone areas has also contributed to an increase in sightings of tornadoes by the human eye—there are more people around, in more geographic areas, than before.

Fourth, was January 2025 the “hottest ever”?

No. It was definitely warm (remember, we’re talking of temperature differences amounting to small fractions of a degree—“warm” seems more fitting than “hot”).

But at least according to NASA’s global satellite temperature monitoring system (most likely the world’s most credible because it’s 24/7/365 all latitudes, all longitudes, all altitudes, unlike surface stations, which are very unevenly distributed around the planet), data from which are managed, in part, by Cornwall Alliance board member and senior fellow Dr. Roy W. Spencer at the University of Alabama Huntsville, last month was “cooler” than each of at least the preceding 12 months—about 0.48C cooler than the “warmest” of them (April 2024) and about 0.16C “cooler” than the “coolest” of them (December 2024).

By the way, the NASA data show a secular [start to end] cooling trend from April 2024 through January 2025—remember what I said about whether we can know if the planet is still warming or has begun cooling from any less than about 5 years of data?

Now, why am I putting “warmer” and “cooler” in quotes? Because what we’re actually talking about here is not simple temperature but temperature anomaly—the difference between a given month’s (or day’s) temperature and the average over a 30-year period (in this case, 1991–2020). These matters are fairly complex, and there’s plenty of room for debate about them. To learn more from a source that is solid in its scholarship but intentionally written for non-experts to comprehend, I recommend our book Climate and Energy: The Case for Realism, with 16 chapters by 16 authors, including 9 climate scientists and several energy engineers and environmental and developmental economists. The book is available from www.CornwallAlliance.org/shop.

This column is adapted from an episode of Created to Reign, the podcast of the Cornwall Alliance for the Stewardship of Creation. You can hear it at Spotify, Apple Podcasts, or through most podcast apps.

Have a question you’d like to ask us? Go to https://cornwallalliance.org/qa-form/.

Featured image courtesy of Dr. Roy W. Spencer.