Review of Climate: The Movie (The Cold Truth) reveals numerous, well-known misinformation talking points and inaccuracies

On 21 March 2024, a movie titled “Climate: The Movie (The Cold Truth)” was released on YouTube, and widely shared on Twitter, Rumble, and other online platforms. The movie gathered more than 1.5 million views on Twitter and 1 million views on YouTube. This 80-minute long film features interviews with climate change contrarians who share their opinions and claims about climate change. Several of the people interviewed are well-known for spreading misinformation and have shared claims which were found to be incorrect or misleading in past Science Feedback reviews. Among them are Willie Soon, Richard Lindzen, William Happer, Steven Koonin, and Ross McKitrick.

While users on Twitter and other platforms have already pointed out numerous inaccuracies in the film, we will further explain the issues with the film’s main claims below. 

Given the numerous claims in this film, we will first investigate three major claims which can be evaluated using well-established science and which have been reviewed in the past by Science Feedback. The main topics of these claims are:

• The climate effects of carbon dioxide (CO₂) compared to changes in solar activity 
• Use of temperature measurements by climate scientists to measure and properly quantify global warming
• Comparing recent climate change to past climate change

Later in the review, we will address the claims which are more nuanced and those which were presented as opinions without supporting data.

Recent Climate Change is Being Driven By Rising CO₂ Levels, Not Solar Variation

One of the main claims in the film – primarily discussed by Willie Soon – is that recent climate change is being driven by changes in solar activity (solar variability), rather than changes in CO₂ concentrations. However, this claim is inconsistent with available scientific evidence, as shown in many past reviews from Science Feedback. To address this claim, we will first investigate and summarize the climate effects of CO₂, and later the negligible effects of solar variability.

The relationship between CO₂ and global temperatures

The relationship between CO₂ concentrations and rising global temperatures is well-established. To investigate the claims made in the film about the climate effects of CO₂, we will summarize key findings from the past reviews linked below:

• Review 1: Link between CO₂ and Earth’s temperature is well-established, despite claims on Fox News
• Review 2: Video of Ian Plimer incorrectly states that human CO₂ emissions are not responsible for increased atmospheric CO₂ concentrations and global warming
• Review 3: CO₂ caused warming during past climate changes, notably as a feedback amplifying other factors

In the film, several broad claims are made about CO₂ and climate change. For example, John Clauser claimed that “there is no connection whatsoever between CO₂ and climate change.” And later in the film, Tom Nelson claimed that “CO₂ levels have changed radically many times. Does this cause temperature change? No! Absolutely not! CO₂ has never driven temperature changes in the past, never.” However, both of these statements are incorrect – the relationship between CO2 and rising temperatures is well-established, and there is clear evidence of their connection in the present and the past. 

In fact, the relationship between CO₂ and global warming was discovered in the mid-19th century, noted James Renwick, Professor at the Victoria University of Wellington, in a previous review. While remaining in the atmosphere, CO₂ prevents heat from escaping and consequently warms the surface of Earth – a concept that is popularly known as the greenhouse effect. This is a consequence of the properties of CO₂, which allow sunlight to pass through to Earth’s surface, but cause CO₂ to absorb and re-emit the energy that returns (i.e., infrared radiation emitted from Earth’s surface after absorbing sunlight)^[1]. Some of the energy that is re-emitted by CO₂ goes out to space, but some is directed back towards Earth and raises global temperatures through the greenhouse effect. From 1990 to 2022, CO₂ caused approximately 78% of the increase in global warming attributed to greenhouse gases. The greenhouse gases overall cause the most global warming of all the climate change drivers, and CO₂ causes the most global warming of all the greenhouse gases (Figure 1). Therefore, contrary to what the film claims, there is a clear, physical explanation connecting CO₂ and climate change, which allows us to quantify how much of the observed warming is due to the CO₂ added by human activities to the atmosphere.

In the film, the narrator claims that “from the mid 19th century, to the mid 20th century, there was only a slight increase [in CO₂]. It’s not until the 1940s that industrial production of CO₂ begins to take off. But this doesn’t match the temperature record.” However, the film’s explanation of global temperature responses to rising CO₂ excluded crucial details about how this response occurs. Namely, that the resulting rise in temperature has been shown to be proportional to the logarithm of the concentration of CO₂, with a time-lag of about 20 years^[3]. The key takeaway from that finding is that to best observe the temperature response, one has to plot it with the correct scaling. When correctly plotted, there is a very strong correlation between rising atmospheric CO₂ concentrations and rising global temperatures as shown on Figure 2 below, contradicting the claim of “no connection” between the two.

When we look back in time, we also see evidence of correlation between CO₂ and global temperatures. For example, this relationship has been observed in paleoclimate data from the last 800,000 years. As shown in Figure 3 below, CO₂ concentrations have clearly oscillated in conjunction with Earth’s temperatures in the past.

Another claim from the film questions why temperature can appear to rise before CO₂ levels rise in past records: “Scientists have indeed found a link between temperature and CO₂. The trouble is, it’s the wrong way around . . . if CO₂ is the driver, it has to change first and the temperature has to change second.” We have already established that rising CO₂ levels correlate to a later rise in temperatures, due to the known time-lag response. However, in addition to the direct forcing of temperature, CO₂ can also contribute to rising temperatures through feedback effects. As explained in a past Science Feedback review, CO₂ has been shown to begin increasing before temperature in some instances of past climate change, but also acted as a feedback that amplified warming caused by other natural factors like cycles in Earth’s orbit. This means that even if other factors were contributing to rising global temperatures, rising CO₂ levels would only have increased temperatures further.

Solar variability is not driving current climate change

Over the years, many false claims have been made regarding the impacts of solar activity on climate change. Science Feedback has addressed this topic in several past reviews, and in each case – now including this film – the claims were inconsistent with available evidence. Below is a brief list of our previous reviews on this topic, followed by a summary of the key findings:

• Review 1: The sun isn’t responsible for current climate change, contrary to claims in Suspicious0bservers YouTube video
• Review 2: Low solar activity has little effect on Earth’s climate, contrary to claim in The Sun
• Review 3: Claim that current climate change can be explained satisfactorily by natural cycles and volcanic activity does not have scientific support
• Review 4: Evidence greenhouse gasses cause global warming denied by Willie Soon in Tucker Carlson interview, resulting in mass social media climate misinformation

The film claims that Willie Soon looked at rural temperature data and determined that “it was obvious that it was the sun, not CO₂, that was driving temperature.” Claiming that solar changes are driving temperature is incorrect; scientists have established several lines of evidence that solar changes are not driving the recent rise in global temperatures. For example, if the Sun were driving global warming, we would expect to see temperatures rising at the surface of the Earth and throughout Earth’s atmosphere. Instead, the data show Earth’s surface heating up, while the layers of the atmosphere are changing variably (i.e., lower altitudes are heating, and higher altitudes are cooling)^[4]. Another review found that the rate and magnitude of modern global warming is too high to be caused by solar variations. As shown in Figure 4 below, solar irradiance and global temperatures show opposing trends; solar irradiance has shown no net increase since 1950, but temperatures have continued to rise.

To put these solar activity trends in context, we can also look further in the past. For example, the Intergovernmental Panel on Climate Change (IPCC), explained that solar activity from the late 19th century to present was not exceptional compared to the last 9,000 years^[2]. The IPCC also shared a figure comparing observed temperature changes to models that account for both human and natural influences (Figure 5). As shown below, in both the observed data and simulated cases, the addition of human drivers–such as CO₂ emissions–lead to a greater rise in global temperatures. These simulations show that human greenhouse gas emissions are the only variable that can reproduce observed temperatures; other natural phenomena, including solar variations, fail to explain the recent rise in global temperatures.

In summary, the hypothesis that the Sun is responsible for climate change is inconsistent with real-world observations. Scientific consensus based on overwhelming evidence shows that greenhouse gasses like carbon dioxide are the main cause of current global warming, beyond reasonable doubt.

Evidence for current global warming rates already accounts and corrects for data bias

When studying temperature trends on Earth, it is important to understand how temperatures can vary between different locations. Similarly, it is important not to conflate the temperature trends at a single location with global trends, as local temperatures can be influenced by factors that do not occur globally. Climate scientists account for these factors when studying global temperature trends; however, the film claims that there are problems with the way temperatures are being measured. We will investigate those claims below. 

The film makes several claims about biases in temperature data. For example, they claim that the Urban Heat Island (UHI) effect (i.e., higher temperatures in urban areas than rural areas) is artificially inflating local temperatures, which are then skewing global temperature trends to seem warmer. This claim has already been investigated in a past review by Science Feedback, and found to be misleading. The findings from this review indicate that although UHI does occur – temperatures tend to be warmer in cities than nearby rural areas – scientists are well-aware that it needs to be properly identified and removed in temperature data series to ensure that global warming is accurately measured. And scientists have made adjustments to account for this. As explained by the IPCC, “The urban heat island phenomenon is well-known and understood. For instance, temperature measurements from thermometers located in cities are corrected for this effect when global warming trends are calculated.”^[2] However, even prior to corrections, the IPCC argued that the uncorrected urbanization influences contribute no more than 10% to the centennial global land averaged temperature trends. This evidence shows that scientists are already aware of the minimal bias from UHI effects and account for this when studying global temperature trends. 

Another topic discussed in the film surrounding temperature bias, is the difference between land and ocean temperatures. In the film they claim that there has been less of a warming trend seen in oceans compared to land. They then suggest that ocean temperature trends are a better representation of global temperature trends because they are not biased by UHI effects. However, this is misleading because it is well known among climate scientists that land heats faster than oceans, and there are physical explanations for why this occurs. One major reason is that, compared to land, oceans have a much higher heat capacity^[5]. This means that for the same amount of supplied heat, land will warm faster than oceans. Another reason for the slower warming is that oceans have a greater ability to cool through evaporation^[6]. According to the IPCC, “The ocean has absorbed about 93% of the combined heat stored by warmed air, sea, and land, and melted ice between 1971 and 2010.”^[5] However, despite the absorbed heat, oceans have still warmed slower than land. The film’s comparison between ocean and land temperatures to support claims about UHI is therefore misleading and excludes well-established scientific evidence.

However, the heat that oceans store is still an important climate change indicator. Scientists have studied how much heat the oceans have absorbed and found that it has increased in recent decades. Li et al. (2023) explained that “ocean heat uptake has accelerated dramatically since the 1990s, nearly doubling during 2010–2020 relative to 1990–2000”^[7]. As the oceans take in more heat, the changes can be measured by looking at the ocean heat content, which shows an increasing trend as shown in Figure 6.

It may also be worth noting the obvious point that humans live on land, and it is therefore the most relevant place to discuss when looking at temperature trends. The observed rate of ocean warming will affect humans over the long term through sea-level rise and ecosystem degradation^[2]; however, rising land temperatures will directly affect humans in daily life. Monitoring temperature trends on land will therefore continue to be important to monitor in the future. 

Recent climate change is unusual compared to past natural variations

The film draws several comparisons between modern climate change and those of the past. The film explains that “We are told that current temperatures are unprecedented and dangerously high. It’s possible to check if this is true, because we have evidence of Earth’s climate history, dating back hundreds, thousands, even millions of years.” However, this statement is misleading and lacks sufficient context. They do not provide a source for this claim, which can mislead the audience into believing that these are the conclusions of climate experts. Additionally, the word ‘unprecedented’ lacks the context of what time frame is being referred to. 

It is well established among climate scientists that periods in geologic time had higher temperatures than present day. However, this does not mean that modern temperature trends do not pose risks to humans. In another part of the film, they compare the temperatures of today to those 500 million years ago–a time that far predates human existence. The temperature conditions from 500 million years ago –prior to human existence– are not a good metric of the optimal conditions for civilization. Instead, we can investigate this claim in relation to temperature data from the Holocene Era –the time where human civilization developed. After analyzing data from this time frame, a number of studies have shown evidence that modern global warming trends are unusual compared to past variations. For example, PAGES 2K Consortium (2019), explains that “the largest warming trends at timescales of 20 years and longer occur during the second half of the twentieth century, highlighting the unusual character of the warming in recent decades.”^[8]
In another study, Kaufman et al. (2020) found that “The distribution of peak global temperatures during the Holocene can also be compared with recent temperatures. The global mean surface temperature of the past decade (2011–2019) averaged 1°C higher than 1850–1900. For 80% of the ensemble members, no 200-year interval during the past 12,000 years exceeded the warmth of the most recent decade.”^[9] The results of this study (Figure 7) show that a rising global warming trend began in the industrial era and has continued to the present day.

This evidence shows that modern warming trends are unusual compared to the recent past, when civilization developed. This is the reason that organizations like the IPCC warn against the dangers of climate change – not because our climate has suddenly become that of when dinosaurs existed, but because we are moving away from the temperatures that civilization, and many living species, are acclimated to. 

Additional Claims

The claims that we investigated above were chosen because they have been well-studied, previously reviewed, and represent the major claims of the film. However, the film contains many other claims that can mislead the audience to a false understanding. The inclusion of dozens and dozens of statements is a well known technique (called gish-gallop) used by misinformers to overwhelm their audience with an excess of information to debunk. Given the film’s excess of claims, we will briefly cover some of the additional claims below. For topics that have been thoroughly covered in the past, we will include a verdict for the claim, brief takeaways, and a link to past reviews when relevant. 

Claim 1 (Incorrect):

Polar bear numbers are growing although they were said to be going extinct

Takeaway:
There is no scientific evidence that the global polar bear population is growing in size. Climate change induced losses in sea ice habitat is the most important threat to polar bear survival. As previously explained in past reviews, there is no scientific evidence that the global polar bear population is growing in size. Although global warming is already reducing the extent of Arctic sea ice, things are expected to become much more extreme, with forecasts of the Arctic becoming ice free in the summer by the middle of this century. Scientists studying polar bears have concluded that climate change induced losses in sea ice habitat is the most important threat to polar bear survival in the future.

Read more in this review: The global polar bear population is threatened by loss of sea ice, contrary to PragerU’s video claim

Claim 2 (Misleading):

The great barrier reef has recently reached record levels

Takeaway:
Research shows that the Great Barrier Reef faces ongoing threats from climate change, including warmer ocean temperatures and more intense tropical cyclones. These threats pose long-term danger to coral reefs and can easily reverse short-term growth in coral cover. Short-term recoveries in coral growth can be reversed quickly, and are not proof that the Great Barrier Reef as a whole is growing. Increases in coral growth have mostly been from the genus Acropora which rapidly grow, but are also susceptible to heat and wave damage^[10]. As explained by Australia’s Tropical Marine Research Agency (AIMS), “large increases in hard coral cover can quickly be overturned by disturbances on reefs where Acropora predominate.”^[10]

Read more in this review: Coral cover in the Great Barrier Reef improved in 2021, but that doesn’t mean the reef is ‘growing quickly,’ contrary to Daily Wire claim

Claim 3 (Misleading):

“you can read in the IPCC reports themselves, that it’s pretty hard to find trends in extreme events, much less attribute them to human influences.”

Takeaway:
There are some aspects of climate science that are clear-cut. It is, for instance, “unequivocal that human influence has warmed the atmosphere, ocean and land,” according to the IPCC^[2]. As human activities emit greenhouse gases into the atmosphere, those greenhouse gas concentrations have increased, causing global temperatures to rise. But it’s harder to draw clear, confident conclusions about the overall impacts of climate change on some global phenomena – including hurricanes. However, as explained in a past Science Feedback review, there are other phenomena, such as heatwaves and intense rainfall events, which have clearly been rising^[11][12]. And these events are expected to continue rising in the future. According to the IPCC, “It is virtually certain that there will be more frequent hot and fewer cold temperature extremes over most land areas on daily and seasonal timescales as global mean temperatures increase.”^[5]

Read more in these reviews:

1. https://science.feedback.org/how-climate-change-impacts-hurricanes/
2. https://science.feedback.org/review/extreme-weather-events-clearly-becoming-common-contrast-lord-lawsons-claim/

Claim 4 (Misleading):

The climate alarm is a scam/hoax. 

Takeaway:
The film does not define the term “climate alarm” when describing it as a hoax/scam. However, the risks that climate change poses to humans and other species on earth is clear. According to the IPCC, “Human-caused climate change is already affecting many weather and climate extremes in every region across the globe. This has led to widespread adverse impacts and related losses and damages to nature and people (high confidence)”^[2].

Claim 5 (Misleading):

The global atmosphere is not warming up as fast as the climate models say it should be.

Takeaway:
This topic has been covered in a previous review by Carbon Brief, which can be viewed here. The findings from this review showed that there has been a close match between projected (modeled) temperatures and observed temperatures since 1970. Although there is not a perfect match, the models are still helpful in predicting future temperature changes. 

Claim 6 (Misleading):

Recent increases in atmospheric CO₂ concentrations are small. 

Takeaway:
Based on findings from a past Science Feedback review, humans have caused an unprecedented rise in atmospheric CO₂ levels compared to the last 800,000 years. Pre-industrialization atmospheric CO₂ levels were around 280 parts per million (ppm)^[13], and reached 419 ppm in 2023 – a 67% increase over that period. Since 1950, the burning of fossil fuels, agricultural development, and other human-caused land-use changes have led to steady increases in atmospheric CO₂. According to the IPCC, “This has led to atmospheric concentrations of carbon dioxide, methane, and nitrous oxide that are unprecedented over at least the last 800,000 years.”^[13][5] Figure 8 below shows the current rise in CO₂ levels in the context of the last 800,000 years.

Read more in these reviews:

1. Human activities have dramatically increased atmospheric CO₂ levels, causing imbalances in the global carbon cycle
2. Link between CO₂ and Earth’s temperature is well-established, despite claims on Fox News

Claim 7 (Misleading):

Higher CO₂ levels of the past lead to a greener world and higher biodiversity. For this reason, we should be thankful that CO₂ levels are going up.

Takeaway:
Based on findings from a past Science Feedback review, plants and animals have different tolerances and responses to elevated CO₂, and concentrations which are optimal for some species can be toxic for others. The fact that elevated atmospheric-CO₂ benefited the dinosaurs and benefits plants today does not mean it also benefits humans. In fact, there are potential human health risks from prolonged exposure to the optimal CO₂ levels for dinosaurs and plants, in addition to the multiple negative environmental impacts for human society resulting from elevated CO₂ and the enhanced greenhouse effect.

Read more in this review: Optimal atmospheric CO₂ for dinosaurs and plants is harmful for humans; current concentration is higher than Homo sapiens have ever experienced

Claim 8 (Misleading):

It is good that CO₂ levels are going up because there is a point at which CO₂ gets low enough where photosynthesis becomes inefficient and plant life has dies, which has happened in Earth’s past. 

Takeaway:
As explained for the claim above, there are multiple negative environmental impacts for human society resulting from elevated CO₂ and the enhanced greenhouse effect. There is no evidence that CO₂ levels on Earth are currently, or anticipated to be, at a point where plant life will be unable to photosynthesize.

Claim 9 (Overstates scientific confidence):

Decreases in the amount of cosmic rays reaching Earth produced less-white clouds, which reflected sunlight and increased global temperatures.

Takeaway:
The connection between the study they reference and past climate events is speculative. In fact, in the words of the authors who published the study, Svensmark et al. (2017) explains that the connection between cloud-seeding from cosmic rays and past climate changes is “conjecture”^[14] – which is defined as an expression of an opinion without sufficient evidence for proof. The authors explained that “the theory of ion-induced condensation should be incorporated into global aerosol models, to fully test the atmospheric implications.” 

Closing remarks on science and consensus

A final theme worth discussing from the film is the nature of science and how scientists reach consensus. As new evidence and data become available, they either increase or decrease the confidence in scientific theories. In the film, Will Happer, claims that “no science is ever settled” as a means of discrediting climate science’s findings. To understand how science works, it is important to note that science does not prove things to be right with 100% confidence, but it can prove things to be incorrect. A more accurate statement about science is that theories can be shown to be true beyond a reasonable doubt. That is, enough scientific evidence can establish very high confidence in a theory (e.g., 99.99% confidence). As observations and experiments give us more data that agree with a theory, the confidence of that theory increases. 

The consensus among climate scientists^[15] about anthropogenic climate change is not built on opinion, but rather on the careful examination of vast sets of available data and realizing that there is agreement between them. At a certain point, a high degree of confidence is built on the subject by those who understand scientific evidence.

REFERENCES

• 1 – Zhong and Haigh (2013) The greenhouse effect and carbon dioxide. Royal Meteorological Society Weather.
• 2 – IPCC (2021). Sixth Assessment Report.
• 3 – Huang and Shahabadi (2004) Why logarithmic? A note on the dependence of radiative forcing on gas concentration. Journal of Geophysical Research: Atmospheres.
• 4 – Santer et al. (2013). Human and natural influences on the changing thermal structure of the atmosphere. Proceedings of the National Academy of Sciences.
• 5 – IPCC (2014). Fifth Assessment Report.
• 6 – Yu (2007) Global Variations in Oceanic Evaporation (1958–2005): The Role of the Changing Wind Speed. American Meteorological Society
• 7 – Li et al. (2023) Recent acceleration in global ocean heat accumulation by mode and intermediate waters. Nature
• 8 – PAGES 2K Consortium (2019) Consistent multidecadal variability in global temperature reconstructions and simulations over the Common Era. Nature Geoscience.
• 9 – Kaufman et al. (2020) Holocene global mean surface temperature, a multi-method reconstruction approach. Nature.
• 10 – Australian Institute of Marine Science (2023). A pause in recent coral recovery across most of the Great Barrier Reef
• 11 – Fischer and Knutti (2015) Anthropogenic contribution to global occurrence of heavy-precipitation and high-temperature extremes. Nature Climate Change
• 12 – Mitchell et al. (2016) Attributing human mortality during extreme heat waves to anthropogenic climate change. Environmental Research Letters
• 13 – IPCC (2007). Fourth Assessment Report
• 14 – Svensmark et al. (2017) Increased ionization supports growth of aerosols into cloud condensation nuclei. Nature.
• 15 – Anderegg et al. (2010) Expert credibility in climate change. Proceedings of the National Academy of Sciences.