Debunking Climate Denial

NIPCC and Climate Change Denialism


To an unsuspecting visitor, the website for the deceptively named Nongovernmental International Panel for Climate Change (NIPCC) looks clean and professional. They purport to be an independent association of scientists that wish to understand factors influencing climate change and the consequences of such changes. They claim that they, unlike the IPCC, look at the full range of evidence regarding the climate and are unfettered by political ideology and bias. However, beneath the surface everything is not what it appeared to be at first sight. NIPCC is a group with overt ties to the conservative anti-science organization known as the Heartland Institute, an organization that has spent a lot of effort trying to spread pseudoscientific uncertainty and doubt regarding the link between second-hand smoke and negative health consequences. They are also one of the most vocal defenders of climate change denialism in the U. S.

Recently, the NIPCC released a report called Climate Change Reconsidered II: Physical Science, calling it an “independent, comprehensive, and authoritative report on the current state of climate science”. In reality, it is a book-length regurgitation of the same stale myths that climate change denialists have been deploying for the past decade in a desperate effort to spread misinformation regarding global warming and the role of human contributing factors. This article examines all of the core claims made by NIPCC in their summary for policymakers. Their list contains thirteen claims, but many of the claims are repeated in different ways (presumably to artificially inflate their position).

Carbon dioxide is not saturated

One of the most persistent myths about carbon dioxide in the atmosphere is that it is either saturated or at the verge of becoming saturated. However, this is based on the false notion that the atmosphere is a single unit instead of being layered. RealClimate explains:

What happens if we add more carbon dioxide? In the layers so high and thin that much of the heat radiation from lower down slips through, adding more greenhouse gas molecules means the layer will absorb more of the rays. So the place from which most of the heat energy finally leaves the Earth will shift to higher layers. Those are colder layers, so they do not radiate heat as well. The planet as a whole is now taking in more energy than it radiates (which is in fact our current situation). As the higher levels radiate some of the excess downwards, all the lower levels down to the surface warm up. The imbalance must continue until the high levels get hot enough to radiate as much energy back out as the planet is receiving. Any saturation at lower levels would not change this, since it is the layers from which radiation does escape that determine the planet’s heat balance.

Satellite measurements also demonstrate that additional greenhouse effects occur as the concentration of carbon dioxide in the atmosphere continue to rise. Essentially, the carbon dioxide is saturated fallacy relies on not understanding that it is the energy balance for the planet depends on the high troposphere. RealClimate sums it up nicely:

So, if a skeptical friend hits you with the “saturation argument” against global warming, here’s all you need to say: (a) You’d still get an increase in greenhouse warming even if the atmosphere were saturated, because it’s the absorption in the thin upper atmosphere (which is unsaturated) that counts (b) It’s not even true that the atmosphere is actually saturated with respect to absorption by CO2, (c) Water vapor doesn’t overwhelm the effects of CO2 because there’s little water vapor in the high, cold regions from which infrared escapes, and at the low pressures there water vapor absorption is like a leaky sieve, which would let a lot more radiation through were it not for CO2, and (d) These issues were satisfactorily addressed by physicists 50 years ago, and the necessary physics is included in all climate models.

Feedback effects are crucial for understanding climate change and cannot be dismissed

In an attempt to minimize the impact of global warming on global average temperatures in the future, the climate change denialists at the NIPCC dismiss feedback effects and claim that the only relevant warming is the direct warming by carbon dioxide and that this warming (which they think is “a few tenths of a degree”) is negligible.

In reality, there is plenty of scientific evidence for positive feedback effects. These include more water vapor in the atmosphere, more carbon dioxide release from the oceans, methane release from the Siberian arctic, drying out of rainforests, decomposition, forest fires, desertification, some cloud feedback, replacement of ice with water and so on. There are also negative feedback effects, such as other kinds of cloud feedbacks, the solubility of carbon dioxide in the oceans, more primary production (i.e. more carbon sinks in photosynthetic organisms) and so on.

However, researchers consider positive feedback process to be stronger than negative feedbacks, so they cannot be minimized or dismissed by climate change denialists.

Global warming has not taken a break

One of the most deceptive techniques used by climate change denialists is to construct trend lines that appear to show that there has been no global warming since 1998 by cherry-picking the start and end points. The following animated graph illustrates this technique:


1998 was an especially warm year due to short-term noise provided by a strong El Niño. If you filter out a lot of the short-term noise, such as El Niño-Southern Oscillation, solar and volcanic activity, there have been no halt in warming since 1998:

Temperature since 1998

This denialist approach also abuses statistical significance tests by asserting that “no statistically significant” warming has occurred since 1998. However, statistical significance relates to how probable the observe data, or more extreme data, are on the null hypothesis, not the practical significance of the observed trend. This alleged “lack of statistical significance” only because of not controlling for the short-term noise.

The concern is that the rate of climate change is faster than during natural variability

One key factor that influences the impact of climate change is the rate at which it takes place. A very slow climate change allows animals and plants to adapt over time to the new climate parameters. A climate change that occur at a faster rate will outpace the evolutionary adaptation and therefore have harmful consequences for animals, plants and regional ecologies.

NIPCC repeatedly deploy the misleading claim that the current temperature and carbon dioxide level has occurred historically and therefore shows that (1) humans are not a considerable contribution factor to the current trends and (2) that these trends do not represent any problem for humans, other organisms or the general environment. As we saw above, this misunderstands the situation. During the natural variability during the Cambrian and recent geological time, organisms had time to adapt and evolve. During periods of rapid climate change, this is unlikely to be the case for a lot of species.

Climate change will have harmful consequences for human health, the economy and environment

Consequences of global climate change includes ocean acidification, coral bleaching, melting glaciers and polar ice caps, rise in sea level, more extreme weather events, changes in the distribution of infectious diseases, species extinctions and so on. There is ample evidence that there will be many harmful effects of climate change on human health, the economy and the environment at large.

Natural forcings alone cannot account for the observed warming

In the synthesis report of AR4 from 2007, we can find the following image:

naturan and anthropogenic forcings

The blue line shows models only taking natural forcings into account, pink lines represents natural and anthropogenic forcings and the black line represents observational data. As we can see, the black line falls outside the blue for each continent, as well as globally. This means that natural forcings alone cannot account for the observed warming trend. Thus, the claim that it is just “all natural” (i.e. no substantial human influence) is falsified by the data.

The carbon dioxide fertilization effect is more complex and variable than NIPCC thinks

It is true that carbon dioxide is the limiting reagent in some areas of the world. More carbon dioxide would therefore mean more plant growth. This could be beneficial by producing more food and more plants to act as sinks for atmospheric carbon dioxide. However, the situation is more complex than that for several reasons. Nitrogen will quickly become a limiting reactant because the proportion of nitrogen per biomass unit produced will decrease. This means that photosynthesis will be down-regulated because a key enzyme in the carbon fixation cycle called Rubisco has a high nitrogen content. Furthermore, plants with different forms of metabolism (C3, C4 and CAM) will react differently and for some this fertilization effect is not as large as previously thought.

Most enzymes have an optimal temperature for which their activity is greatest. Lower temperatures reduces the number of interactions that has sufficient energy to overcome the activation energy required for reaction. Too high temperatures over the optimum and they start to lose their three-dimensional structure that is often vital for their proper function. Some plants may currently grow in a climate were the temperature is below the optimal temperature, and so an increase in temperature will lead to a higher enzyme activity. But there are probably also those plants that grow in areas were the temperature is above the optimal temperature, and an increase in temperature will lead to an even lower enzyme activity. This means that there are places around the world were global warming will lead to less crop success and yield, even when taking into account the carbon dioxide fertilization effect.

There are also related issues surrounding agriculture that needs to be taken into account, such as water supply and large-scale fires. There is no guarantee that water supplies will not be affected by droughts and floods and a higher frequency of wildfires could be devastating for agriculture.

Bidirectional causation between higher temperatures and more atmospheric carbon dioxide

No one is claiming that carbon dioxide is the only factor that had contributed to climate change in the history of the earth. Rather, the claim is that human emissions of carbon dioxide and other anthropogenic greenhouse gases is a substantial influence on the current warming trend.

Large-scale changes in orbital forcings by natural changes in eccentricity, tilt and precession contributed to the end of the last ice age. This initial warming cause additional carbon dioxide to enter the atmosphere from the ocean, which lead to even more warming. The “carbon dioxide lags temperature” diversion falls apart once you notice that more carbon dioxide and higher temperature cause each other in a feedback process.


The Heartland Institute is ramping up their attempt to spread misinformation about climate change and global warming by having their deceptively named organization NIPCC putting out pseudoscientific and denialist “reports” that amount to little else than the mindless repetition of denialist myths that have been refuted many times previously.

References and further reading

Real Climate: A Saturated Gassy Argument.

Skeptical Science: Is the CO2 effect saturated?.

IPCC: AR4 Synthesis Report: Global and continental temperature change.

Real Climate: CO2 fertilization.

Skeptical Science: CO2 is plant food.

Real Climate: The lag between temperature and CO2. (Gore’s got it right.).

Skeptical Science: CO2 lags temperature – what does it mean?.

Skeptical Science: Positives and negatives of global warming.


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