Commentary in The Australian ignores evidence and misrepresents research while falsely claiming humans are not responsible for climate change

„Global human emissions are only 3 per cent of total annual emissions.”

Sara Vicca, Postdoctoral research fellow, University of Antwerp:
Global human emissions are indeed only a small percentage of what ecosystems cycle, but the reasoning is completely flawed. Regarding the impact on climate, it is the net emissions that matter, not the amount of carbon that is being cycled over and over. Terrestrial ecosystems take up and re-emit about 12 times more CO₂ than humans emit, and oceans cycle about 9 times more CO₂ than we emit. BUT! This carbon uptake and release is more or less balanced at the annual scale, and net ecosystem emissions are even negative. Without these ecosystems, atmospheric CO₂ concentration would have risen even more as a consequence of fossil fuel burning; the CO₂ concentration in the air would already be around 550 ppm (instead of the current ~400 ppm). Hence, it is absolutely misleading to compare amounts of CO₂ cycling through the ecosystems with human CO₂ emissions in this context. If anything, the CO₂ cycling through the ecosystems should be taken as a reason to safeguard them: if we lose these carbon sinks, CO₂ in the air will increase no matter what we do.

Ana Bastos, Scientific Researcher, Ludwig-Maximilians University of Munich:
This is purposely misleading. Others have commented appropriately. The global carbon budget provides an overview of sources and sinks of CO₂ since 1880.

Source: Global Carbon Project

Peer Nowack, Independent Research Fellow, Imperial College London:
Others have already commented on this in detail. Just to emphasize: the statement is clearly misleading. What matters here is how human emissions drive the net atmospheric CO₂ budget (emissions minus uptake) out of balance, which leads to an accumulation of CO₂ in the atmosphere.

„It has never been shown that human emissions of carbon dioxide drive global warming.”

Peer Nowack, Independent Research Fellow, Imperial College London:
This sentence essentially ignores many thousands of studies that provide evidence to the contrary (i.e., that human CO₂ emissions ARE driving global warming) and is therefore factually wrong.

• IPCC (2013) Climate Change 2013: The Physical Science Basis

Wolfgang Cramer, Professor, Directeur de Recherche, Mediterranean Institute for Biodiversity and Ecology (IMBE):
Virtually all statements in this article have been proven wrong so many times by scientific experts that it is unreasonable to once again show that they are wrong. But I want to focus on the statement „it has never been shown“ only. How can one claim that the impact of anthropogenic greenhouse gas emissions has „never been shown that…“? Clearly, for this author, science per se either does not exist or else has no credibility whatsoever. Surely then, scientific research itself cannot exist, there is no geology to find coal resources, no studies „of natural processes such as ocean degassing“, etc. From this, one can only conclude that we actually cannot know anything—not even the things that this author believes to be true.

This is not true. In fact, there is a vast body of work on detection and attribution, which specializes in exactly this: determining the causes of observed changes in climate. This happens in a two-step process. Step 1 (the detection step) looks at whether observed changes can be explained by internal climate variability. If the answer is no, step 2 (the attribution step) determines which factors explain the observed changes.

„natural processes such as ocean degassing, volcanoes, natural chemical reactions and exhalation don’t drive global warming.”

Peter Neff, Postdoctoral research associate, University of Washington:
Here is a great illustration of how these processes don’t drive warming over the observational period: https://www.bloomberg.com/graphics/2015-whats-warming-the-world/

„In the geological past, Earth’s atmosphere had hundreds of times the CO2 content of the modern atmosphere yet there were no carbon dioxide-driven catastrophes. The past shows that climate change is normal, that warmer times and more atmospheric carbon dioxide have driven biodiversity and that cold times kill.”

Peer Nowack, Independent Research Fellow, Imperial College London:
There are many problems with this statement, starting with an entire lack of accuracy. It reads like a series of generic statements that can easily be taken out of context and are entirely irrelevant to the problem at hand. One particularly striking point is the implicitly obvious lack of awareness for timescales. Atmospheric CO₂ concentrations are changing at unprecedented rates now, posing a serious threat to biodiversity in rapidly changing ecosystems.

Indeed, climate change is normal, but there are 2 important differences with respect to the geological record: 1) the current rate of increase in CO₂ is unprecedented and 2) the current CO₂ increase is caused by human emissions.

„Ice core drilling shows that 800 years after natural warming, the atmosphere increases in carbon dioxide”

Nathaelle Bouttes, Research scientist, CNRS, Laboratoire des Sciences du Climat et de l'Environnement (LSCE):
Recent work* shows that the temperature and CO₂ rise were synchronous within uncertainties: if there was a lag it was less than 400 years, not 800 years as previously thought. Additionally, the temperature increase over the deglaciation cannot be explained solely by orbitally driven insolation changes (modifications of solar energy received by the Earth due to its position). The radiative effect of the CO₂ rise amplifies the warming and explains part of the total deglacial warming.

• Parrenin et al (2013) Synchronous Change of Atmospheric CO2 and Antarctic Temperature During the Last Deglacial Warming, Science

„Instrumental temperature measurements over the past 150 years show no correlation between human emissions of CO2 and ­temperature.”

Emmanuel Vincent, Research Scientist, University of California, Merced:
Plotting the relationship between global temperature and the logarithm of atmospheric CO₂ concentration shows a strong relationship (figure below). This is predicted by physics* since CO₂ is a greenhouse gas. Ian Plimer might be confusing CO₂ emissions and CO₂ concentration in the atmosphere, which is what matters for explaining Earth’s surface temperature.

Figure – Global temperature from Berkeley Earth’s dataset versus atmospheric CO₂ concentrations.

• Huang and Shahabadi (2014) Why logarithmic? A note on the dependence of radiative forcing on gas concentration, Journal of Geophysical Research Atmospheres

Peter Neff, Postdoctoral research associate, University of Washington:
Instrumental temperature measurements over the last 150 years record weather/climate that is influenced by more than ONLY CO₂. Natural variation must also be considered, including semi- to multi-decadal processes involving the ocean and atmosphere (e.g. El Niño-Southern Oscillation).

„On all timescales it can be shown that there is no correlation between CO2 emissions and global warming.”

Peter Neff, Postdoctoral research associate, University of Washington:
This is simply false. Ice cores show correlation over ice age cycles (100,000 years).

The modern observational record shows correlation that cannot be reproduced without including greenhouse gases (CO₂, CH₄, N₂O). Climate models demonstrate this correlation very well. If you include only natural climate forcing (volcanoes, solar variations, etc.) over the observational period, models UNDERpredict observed temperatures. If you include only greenhouse gas forcing over the observational period, models OVERpredict observed temperatures. If you include natural, greenhouse gas, and other anthropogenic forcings (including cooling effects of coal/soot pollution particulates), models quite accurately match observations.

Comparison between global mean surface temperature anomalies (°C) from observations (black) and AOGCM simulations forced with (a) both anthropogenic and natural forcings and (b) natural forcings only.

Source: IPCC

„The worldwide temperature record has been changed. Cooling trends have been ‘homogenised’ to warming trends. In the corporate world, if a loss is ‘homo­genised’ to a profit, it is fraud.”

Peter Neff, Postdoctoral research associate, University of Washington:
This point has been refuted ad nauseam. See Zeke Hausfather’s explaination here: https://www.carbonbrief.org/explainer-how-data-adjustments-affect-global-temperature-records

Berkeley Earth independently assessed these records. The adjustments, which are necessary over 150-200 years of measurements of varying type and quality, end up reducing the warming trend over the 20th Century.

Ana Bastos, Scientific Researcher, Ludwig-Maximilians University of Munich:
Every time new data is assimilated, the record is bound to change slightly. I think the author is referring to a discontinuity in the global temperature record around 1945 that was shown to be due to changes in the instruments after WWII*. Since this discontinuity was reported, new temperature products were corrected for instrumentation change. This is not fraud, just good science.

• Thompson et al (2008) A large discontinuity in the mid-twentieth century in observed global-mean surface temperature, Nature

„[South Australia] has the most expensive electricity in the world.”

Kenneth Gillingham, Associate Professor, Yale University:
This is misleading. It is true that prices have rapidly increased, largely due to high natural gas prices from the start-up of gas liquefaction plants. However, there are plenty of other regions within countries (note South Australia is a region within the country of Australia) with just as high or higher electricity prices. How about villages in Alaska? Small islands? This claim is just misleading.

„Unless the laws of physics are changed, solar power cannot be made more efficient.”

Kenneth Gillingham, Associate Professor, Yale University:
This is incorrect. Sure, if you use exactly the same technologies we have today there is a barrier to the efficiency of polycrystalline solar panels. But there are many other technologies in the works that can have much higher efficiency.

• Lew (2016) Research opportunities to advance solar energy utilization, Science

„Construction and maintenance of wind and solar facilities ­release far more carbon dioxide than they are meant to save over their working lives and they need to be sup­ported 24/7 by coal-fired generators.”

Kenneth Gillingham, Associate Professor, Yale University:
This is completely incorrect. There are numerous studies contradicting this. For example, see a series of studies by Sally Benson at Stanford University. Frankly, both parts of this claim are absurd. Coal-fired generators are particularly poorly-suited to act as a backup for solar because they generally are very expensive to ramp up and down, so they are used almost everywhere around the world as baseload generators. Natural gas or hydro are much better suited as backup. This sentence belies a lack of understanding of energy technologies and markets.

„[Those who signed the Paris Accord] cannot change Earth’s orbit and radiation released from the sun that drive climate”

The problem we are dealing with here is not the radiation released from the sun, but with the amount of energy that remains in the Earth’s climate system. The amount of energy trapped in the climate system increases due to the presence of greenhouse gases in the atmosphere: rather than shooting the energy back into space, it is used to heat the climate system. Simple physical laws, that make that more greenhouse gases cause a warmer climate.

• NASA’s Earth Observatory has an extensive explanation.

Peter Neff, Postdoctoral research associate, University of Washington:
This links back to the author’s earlier claim about ice cores, that they show increasing CO2 after „natural warming.“ In this ancient scenario, he is correct that warming was caused by changes in Earth’s orbit around the Sun—which slightly but significantly affects the planetary energy budget. However, it is no longer the case that solely Earth’s orbit and solar radiation drive climate change. Solar energy reaching Earth has been declining for decades, as global average temperatures have continued to increase. Zeke Hausfather has nicely explained this.

„Australia’s signed a suicide note [with the Paris Accord] yet didn’t seem to notice that China, India, Indonesia and the US did not commit to reducing their large carbon dioxide emissions.”

China and India are actually changing track. They need to because their people are dying of air pollution. And of course they have also realized that renewable energy is more profitable. See here fore much more information: https://www.worldenergy.org/publications/2017/world-energy-issues-monitor-2017/

Statement taken from the full report of 2017: “China is continuing to experience rapid growth in renewable energy capacity, with the country installing 30.8 GW of new wind capacity in 2015, and with government plans in place to build an additional 30.83 GW before the end of 2016. The country’s solar capacity, too, is increasing steadily and China has already overtaken Germany to become the country with the largest cumulative solar PV capacity globally. Regarding future investment in further renewables capacity, China claims the top spot in the 2015 Climatescope project, which ranks 55 emerging economies according to their ability to attract investment in clean energy, and places second globally after the US in Ernst and Young’s 2016 Renewable Energy Country Attractiveness Index.”

„The grasslands, crops, forests and territorial waters of Australia absorb more carbon dioxide than Australia emits.”

Ana Bastos, Scientific Researcher, Ludwig-Maximilians University of Munich:
This is not true. According to the CSIRO (see here): “Taking all fluxes together, the Australian biosphere gained carbon on average at 59 million tonnes of carbon per year (1 Mt = 1 Teragram, Tg) during the period 1990-2011. This amount is the equivalent to 62% of Australia’s emissions from fossil fuels for the same period (this calculation excludes the fossil fuel exports shown in the budget figure).”

Source: CSIRO

A thorough analysis of the Australian carbon budget can be found in Haverd et al*.

• Haverd et al (2013) The Australian terrestrial carbon budget, Biogeoscience