Apocalyptic fears have been generated without foundation.

By Epp Tuul

The US Department of Energy (DOE) recently published a report examining the impact of carbon dioxide emissions on ecosystems and society. The report’s authors, leading scientists in the field, estimate that the impact of CO2 is significantly smaller than previously thought and find no basis for climate panic. In other words, they argue that climate science has largely relied on science fiction in recent years and has created unfounded apocalyptic fears. Freedom Research has the story.

The report was commissioned by the US Energy Secretary Christopher Wright and was authored by climate researchers from several universities and institutes: John Christy, Judith Curry, Steven Koonin, Ross McKitrick, and Roy Spencer, of whom Curry and McKitrick have previously given interviews to Freedom Research as well.

The researchers reviewed scientific articles and data from 2020 to 2024 and assessed how greenhouse gases, and CO2 emissions in particular, affect the climate, extreme weather conditions, ecosystems, agriculture, and the economy in general.

The report’s findings challenge several widely accepted climate assumptions. For instance, they state that CO2 promotes plant growth worldwide and has led to a significantly greener world in recent decades. Additionally, the more CO2 humans have produced, the faster nature has removed it from the atmosphere. The authors also note that historical US data shows no increase in the frequency or intensity of hurricanes, tornadoes, floods, or droughts compared to the past. They further confirm that the belief in increasingly acidic oceans and disappearing coral reefs is incorrect, as pH changes remain within historical variability, and coral reefs, such as the Great Barrier Reef, are showing signs of recovery.

Finally, the scientists call for climate policy to be evidence-based, emphasizing the need for realistic emission scenarios, improved climate models, and recognition of CO2 benefits, such as enhanced agricultural productivity. The report challenges panic-driven narratives and argues that global energy shortages pose a far greater threat than climate change.

The World Is Twice as Green as It Was a Few Decades Ago

According to the study, carbon dioxide plays a dual role in making the world greener. It promotes photosynthesis and the efficient use of water by plants, thereby improving plant growth (Drake et al., 1997). Plants absorb CO2 through pores on the surface of their leaves. When there is little CO2, the pores must remain open for a long time, allowing water to evaporate. However, when CO2 is abundant, the leaf pores remain closed for longer, helping the plant to conserve water and thereby increase its water use efficiency.

According to satellite data, the area covered by vegetation has increased by 25-50% since the 1980s, mainly due to CO2. A 2016 study by Zhu et al was one of the first to confirm that between 1982 and 2011, the world became a quarter to a half greener, while only 4% became “browner.” Researchers attributed 70% of the greening to higher CO2 levels, with other factors including land use changes, warming, and nitrogen. This was confirmed by a 2017 study by Zeng et al, which found that global leaf area has increased 8% over 30 years and that an increase of lush vegetation mitigates warming.

In the DOE report, researchers note that CO2 levels in the atmosphere have fallen steadily over millions of years. Geological evidence shows that plants and animals evolved during a period when CO2 levels were much higher than they are today. However, if CO2 levels in the atmosphere had continued to decline, plant growth would have slowed and eventually ceased (Gerhart & Ward, 2010), as only a few plant species can grow in conditions of extremely low CO2 levels.

In addition, research has been conducted on how changes in CO2 levels affect agriculture. For instance, higher CO2 levels positively impact the yield of corn, wheat, rice and soybeans by enhancing photosynthesis and reducing water loss (see also Deryng et al., 2016; Cheng et al., 2017). Even in regions where dry conditions show signs of worsening, plant productivity (e.g., biomass and photosynthesis) is generally maintained because elevated atmospheric CO2 levels fertilize plants and improve water use efficiency (Zhang et al., 2024). Thus, the positive effects of CO2 largely offset the negative impacts of global warming and drought in most regions. Agricultural yields are higher, and the increased productivity due to CO2 compensates for potential yield reductions caused by warming. Only up to 4% of current dry areas face conditions where higher CO2 levels do not mitigate losses, potentially leading to desertification. According to the US report, the Intergovernmental Panel on Climate Change (IPCC) addresses the greening of the world and CO2’s role as a plant fertilizer only briefly (e.g. in the 6th report). Although the IPCC acknowledges with high confidence that the world has become greener over the past two to three decades, there is low confidence about the extent of this trend.

Oceans Remain Alkaline, Not Acidic

The pH of pure water is 7.0, with higher values indicating alkalinity and lower values indicating acidity. The average pH of the ocean’s surface layer is currently estimated at 8.04 (Copernicus Marine Service), down from an estimated 8.2 before the industrial era. As atmospheric CO2 levels have risen, oceans have absorbed more CO2, slightly reducing their pH. Depending on the oceans’ buffering capacity, they are expected to become marginally less alkaline over time, consistent with the observed pH decline.

According to the DOE report, the term “ocean acidification” is misleading because the oceans are not expected to become acidic. Scientists recommend using the more accurate term “ocean neutralization” instead. The report notes that marine life evolved when oceans were slightly acidic, with a pH of 6.5–7.0 (Krissansen-Totton et al., 2018). Marine life is thus resilient to pH changes, having adapted to a wide range of pH values.

The claim that decreasing seawater pH reduces coral reef calcification is also questioned. The report’s authors highlight that coral reefs tolerate significant pH fluctuations, partly due to daily photosynthesis, with measured pH values ranging from 9.4 during the day to 7.5 at night. A 2009 study by De’ath et al suggested that 14% of the Great Barrier Reef had been calcifying 14% slower since 1990, attributing this to higher water temperatures and lower pH. However, Ridd et al (2013) demonstrated that this study relied on inconsistent data analysis, and corrected data showed no change in calcification rates. Despite this, the original study has been cited 541 times, compared to only 11 citations for the correction (as of April 30, 2025). The Australian Institute of Marine Science’s latest annual report confirms strong recovery in coral production. Prior deterioration of the Great Barrier Reef before 2011 was largely due to tropical cyclones (Beeden et al., 2015), marine heatwaves, agricultural pollution, and invasive species (Woods Hole, 2023).

In summary, the US report argues that the impact of ocean neutralization on corals has been exaggerated and one-sided. Studies claiming severe impacts from pH decline have gained more traction, despite evidence to the contrary. This bias is illustrated by Browman’s 2016 study, which notes: “As is true across all of science, studies that report no effect of OA are typically more difficult to publish”.

Climate Models Overestimate Global Warming

The report states that global climate models overestimate warming and rely on emission scenarios that often exceed actual trends. Thus the models’ conclusions are overly pessimistic, predicting greater warming of the surface and troposphere than observations indicate. Predicting the future is challenging, and carbon dioxide emissions, along with the impact of human activity on the climate, depend on many factors, including demographics, economic activity, regulations, and energy and agricultural technologies. The high degree of uncertainty surrounding these factors makes it impossible to accurately predict future emissions. However, the IPCC uses a set of scenarios representing a range of likely outcomes for population, economy, and technology. These scenarios show the expected anthropogenic radiative forcing for the year 2100. For example, IPCC scenario number 6 projects 6 W/m² of anthropogenic radiative forcing (warming) by the end of the century. The current anthropogenic radiative forcing is approximately 2.7 W/m².

Although the IPCC does not claim its emission scenarios are predictions, they are often treated as such. However, comparisons of the IPCC’s previous scenarios with actual observations show that the IPCC’s emissions projections tend to overestimate actual emissions (McKitrick et al., 2012; Burggess et al., 2021; Hausfather & Peters, 2020; Pielke et al., 2022). Many scientists argue that to have better climate policies, the use of worst-case scenarios should be discontinued, as the most negative scenario is also the least likely. According to Pielke and Ritchie (2020), the climate research community has spent a decade devoting scientific resources to creating ‘science fiction’, and scientific literature is skewed toward apocalyptic scenarios.

The Impact of Humans and Carbon Dioxide Levels on the Climate Is Less Significant Than Expected

Scientists acknowledge that the climate is naturally variable throughout Earth’s history. Anthropogenic CO2 emissions increase this variability by altering the balance of radiative energy in the atmosphere. However, the IPCC has assessed the role of the Sun in climate change as minimal, based on data reconstructions showing that changes in solar radiation have had little impact since pre-industrial times. Yet, data from 1600 to 2000 suggest both possibilities: that 20th-century warming is unrelated to the Sun, or that it is influenced by solar activity (Connolly et al., 2021). Thus, the IPCC’s “consensus” on the minimal role of solar radiation is premature, potentially overlooking scientific opinions that present dissenting views.

In addition to the Sun, volcanic aerosols contribute to natural radiative forcing with an episodic cooling effect. The IPCC AR6 report discusses the impact of volcanic eruptions on climate, citing three eruptions in the first half of the 19th century. For example, the 1815 Tambora eruption caused “a year without a summer” and widespread crop failures in the northern hemisphere. However, after the 1991 Pinatubo eruption, atmospheric CO2 levels temporarily decreased, an intriguing result that remains unexplained to this day (Angert et al., 2004).

The warming effect of carbon dioxide depends largely on how much “additional” CO2 is accumulated in the atmosphere, i.e. on concentrations exceeding the pre-industrial value of 280 ppm. The CO2 level recorded at the Hawaii Mauna Loa Observatory is typically used as an indicator of the global average concentration. Recordings began in 1959, when the level was around 316 ppm. Currently, the CO2 level is approximately 430 ppm, representing an increase of about 36%. At the end of the last Ice Age, CO2 levels had fallen to around 180 ppm, where further declines could have threatened plant life.

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