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A Few Facts about the Changing Climate

A Few Facts about the Changing Climate

The thermometer was invented in 1654, 369 years ago, while the age of the Earth is 4.54 billion years. If my math is correct, we have a temperature ‘record’ for the planet of only 0.00001% of Earth's history. How do we know this was the warmest July ever?

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Over the summer, it started to annoy me that the media’s coverage of the unfolding climate crisis is so biased. Don’t get me wrong – I also think we have a problem, but human behaviour is not the only problem, and the media shouldn’t be so blatantly one-sided. There is far more to the climate story than the media want you to believe, and this paper is an attempt to cover ‘the other side’.

As you can see from the quote above, my frustration with the ongoing climate debate is shared by at least one ARP+ subscriber, and I can assure you – he is not alone. My inbox can provide plenty of proof of that.

Don’t expect me to argue that humans are innocent victims of the climate crisis. For what it is worth, I don’t think we are, but I believe it is important that all aspects of the unfolding crisis are shared with the public. I often come across points made in the media that are either blatantly wrong, or they are not particularly well researched but presented as if they are undeniable facts.

Lack of statistical significance

If you are my age or older, you may remember (as I vividly do) how the media, back in the 1970s, liked to tell us that we were heading for the next ice-age. There were even books published on the topic. Take for example Nigel Calder's The Weather Machine, published by the BBC in 1974 and accompanied by a so-called documentary of the same name, which was nothing of the sort.

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In 2008, Thomas Peterson, William Connolley and John Fleck published a paper in American Meteorological Society, called The Myth of the 1970s Global Cooling Scientific Consensus, which you can find here.  The three gentlemen classify the ‘global cooling’ of the 1970s and early 1980s as pure and simple media spin. They do not argue that the current episode of global warming is necessarily the same but warn against drawing conclusions on data that is statistically insignificant. As they conclude: “Never let the truth get in the way of a good story”.

ENSO – aka El Niño & La Niña

El Niño and La Niña, two famous weather phenomena, are part of a weather system called ENSO which has always existed. It has nothing whatsoever to do with human activities. ENSO is a natural weather phenomenon in the global climate system, resulting from variations in ocean temperatures in the Equatorial Pacific. El Niño warms up the Earth, and La Niña – El Niño’s cooling opposite – cools it down again.

ENSO is the most influential natural climate pattern on Earth. It swings back and forth every few years with both El Niño and La Niña affecting the oceans as well as the atmosphere. An average El Niño raises the global average temperature by 0.2-0.3°C. Three points on that:

(i) Although the average El Niño raises the temperature by 0.2-0.3°C, there are examples of more powerful El Niños, where the global average temperature has risen as much as 0.5°C.

(ii) When the global average temperature rises by 0.2-0.3°C, parts of the world will see a temperature increase in excess of that, and the polar regions stand out in that respect.

(iii) Extreme weather events don’t rise proportionally with a rise in the temperature. Rather, it takes only a small increase in the temperature to have a dramatic impact on the weather.

Therefore, in El Niño years, one shouldn’t be that surprised to see a rather steep increase in the number of extreme weather events. El Niño arrived in the spring and will most likely be with us for at least a couple of years. Then again, no model exists that can predict, with any level of accuracy, how long El Niño will stay with us.

The tilt of the Earth’s axis

CO2 levels in the atmosphere are on the rise. That is an undeniable fact (Exhibit 1), and anybody arguing otherwise hasn’t done their homework.  The chart below was last updated in 2022, at which point the CO2 concentration level averaged 417.1 ppm.  Now, a year later, we are at 421 ppm.  Prior to the industrial revolution, the highest level of CO2 in the last 800,000 years occurred some 320,000 years ago when it stood at 300 ppm. We don’t have data going any further back.

Exhibit 1: CO2 emissions over the last 800,000 years
Note: Past CO2 levels can be reconstructed from ice cores.

I am in no doubt that the rather steep increase in CO2 concentration levels more recently is overwhelmingly the result of human activities since the early days of the industrial revolution. Nor do I question the argument often raised that the rise in CO2 concentration levels has affected the temperature. However, if CO2 levels drive the temperature on Earth more than anything else, now should really be the warmest we have ever experienced on Earth but it isn’t. Why is that?

During an era called the Eemian Period some 120-130,000 years ago, it was noticeably warmer than it is now. The Eemian Period is also called the Interglacial Period, as it was a warm spell between two ice ages.  During Eemian times, the winters in the northern hemisphere were particularly warm with the average temperature in the Arctic region being about 3°C higher than it is now.

Adding to that, scientists have found that about 8,500 years ago, it was warmer in the Arctic region than it is now. Do these two episodes of warm weather have anything in common? The answer to the question is yes. The Earth’s axis is tilted at an average angle of 23.5 degrees. During the Eemian Period and the more recent episode in the Arctic, the tilt was close to its maximum 24.5 degrees. Allow me to quote NASA:

The angle Earth’s axis of rotation is tilted as it travels around the Sun is known as obliquity. Obliquity is why Earth has seasons. Over the last million years, it has varied between 22.1 and 24.5 degrees with respect to Earth’s orbital plane. The greater Earth’s axial tilt angle, the more extreme our seasons are, as each hemisphere receives more solar radiation during its summer, when the hemisphere is tilted toward the Sun, and less during winter, when it is tilted away. Larger tilt angles favour periods of deglaciation (the melting and retreat of glaciers and ice sheets). These effects aren’t uniform globally – higher latitudes receive a larger change in total solar radiation than areas closer to the equator.

This phenomenon is also known as the Milankovitch Cycle. It doesn’t explain the current episode of warming, as the Earth’s axis is currently tilted at 23.4 degrees, i.e. marginally below average; however, I bring it up to illustrate that the global weather system is terribly complex, and that you cannot simplify things as much as is often done in the media.

The end of the Gulf Stream?

Recently, media reports have been busy telling us that the Gulf Stream is about to collapse. The Gulf Stream is a current that brings warm water from the Gulf of Mexico into the Atlantic Ocean. It extends up along the east coast of the US and Canada, before it crosses the Atlantic Ocean, and that explains why Northern European winters are so much warmer than, say, Canadian or Siberian winters (Exhibit 2).

Exhibit 2: The pattern of the Gulf Stream

If the Gulf Stream were to collapse, the consequences would indeed be dire. One of the most densely populated areas in the world would suddenly suffer from Siberian winters. The winter temperature in Northern Europe would be about 10°C below current levels.

The Gulf Stream is caused by ocean gyres – a system of circular currents and powerful winds. There are five oceanic gyres on Earth. The Gulf Stream is part of the North Atlantic Subtropical Gyre. The Atlantic Meridional Overturning Circulation (AMOC for short) is part of this gyre, and AMOC is where the problem lies. It is now at the weakest point of the last 1,600 years, most likely caused by global warming, and researchers have projected it will collapse in the foreseeable future (you can find the paper here).

The problem is that the media don’t understand the difference between AMOC and the Gulf Stream. As Dr. Jonathan Foley, climate scientist and executive director of Project Drawdown, says: “The Gulf Stream and AMOC are not the same thing. Not at all. It’s like comparing a superhighway with a side street.” And he continues: “This current is caused by wind patterns in the tropics and mid-latitudes, plus the Earth’s rotation. As long as the wind blows and the Earth rotates, the larger Gulf Stream is going to continue. There is zero chance that it will collapse.” (source:

Final few words

I should probably stop here.  If you believe I have suddenly turned into a climate sceptic, I have done a poor job of explaining myself. I just prefer to have all the facts – and nothing but the facts – on the table, when I draw my conclusions.  There are far too many silly climate stories in circulation right now. One example: Exhibit 3 below has been used extensively in recent weeks to paint a very gloomy picture. The 4th of July was indeed the hottest day on record but not necessarily the hottest day ever. As the ARP+ subscriber dryly observed, the thermometer was not invented until 1654!

Exhibit 3: Average global air temperature at 2 metres above the surface
Source: Guardian

It is a single observation taken from the playbook of a planet that is about 4.5 billion years old – and it was taken in an El Niño year. We know a fair bit about what has happened on Earth over the last few hundred thousand years, but do we know everything? Certainly not. Human nature, on the other hand, is such that we think we can control absolutely everything. In this case, I think we are a bit too ambitious.

Having said that, from an investment point-of-view, it will matter little what I or a few sceptics think or say. As long as the vast majority of investors think the end is nigh, companies positively exposed to climate change will be in vogue. And that is an opportunity it would be silly to miss, whether you think facts are misrepresented or not.

Before you start bombarding me with well-meant emails, I want to emphasize one critical point. I wholeheartedly agree that we should try and impact what can be impacted, i.e. CO2 emissions. All I want to say with this paper is that there is an awful lot going on in the climate system that is beyond human control, and the media would grow in my estimation if they recognised that.


7 September 2023

About the Author

Niels Clemen Jensen founded Absolute Return Partners in 2002 and is Chief Investment Officer. He has over 30 years of investment banking and investment management experience and is author of The Absolute Return Letter.

In 2018, Harriman House published The End of Indexing, Niels' first book.