• Climate

Ian Plimer op-ed in The Australian again presents long list of false claims about climate

Posted on:  2019-11-26

Reviewed content

Headline: "Let’s not pollute minds with carbon fears"

Published in The Australian, by Ian Plimer, on 2019-11-22.

-2 scientific credibility
"-2" verdict chart image

Scientists’ Feedback

SUMMARY

This op-ed in The Australian by Ian Plimer, titled “Let’s not pollute minds with carbon fears”, makes many claims: that polar ice is not melting, that human-caused CO2 emissions can’t cause climate change, that all life on Earth would die if CO2 levels dropped to half of current levels, and so on. None of these things are true.

As was the case with three other op-eds written by Plimer that we evaluated previously, reviewers unanimously rated the scientific credibility of this article “very low”. In their comments below, the scientists identify a large number of inaccurate or incorrect statements about the way Earth’s climate system works, how climate has changed during Earth’s history, and what we know about the impacts of continued climate change.

See all the scientists’ annotations in context. You can also install the Hypothesis browser extension to read the scientists’ annotations in context.

REVIEWERS’ OVERALL FEEDBACK

These comments are the overall assessment of scientists on the article, they are substantiated by their knowledge in the field and by the content of the analysis in the annotations on the article.

Mark Richardson member picture

Mark Richardson

Research Associate, Colorado State University/NASA JPL

This article will mislead readers. It uses nonsense logic, is clueless about the science, and says things which are wrong. Some of these false statements have been obviously wrong for years.

One example is claiming “[i]t has never been shown that human emissions of carbon dioxide drive global warming.” This shows cluelessness about decades of important research. Direct measurements1 show that more atmospheric CO2 is causing enough heating to explain the observed warming, and we know that the CO2 rise is caused by us2. Those studies are two of hundreds that have built the overwhelming case that human CO2 emissions are now driving global warming.

Climate models are computer programs that crunch equations describing the laws of physics, and they also calculate that rising CO2 is driving the observed warming. They include changes in solar activity, and a study from 20063 found that climate models calculate strong effects of clouds on global warming—they could either amplify or slow CO2-driven warming. It is completely fake of Plimer’s article to say that “[t]he role of the sun and clouds was not considered important by modellers”.

Since our CO2 emissions are the main driver of recent warming, we expect a correlation between these emissions and global temperature. By plotting temperature against emissions and using standard statistics we can calculate the correlation, this example is for 1959—2014 (the correlation gets stronger if you use other datasets which extend to 2018).

plot showing correlation between CO2 and global temperature

The data show a strong correlation since 1959, with temperatures being higher when cumulative human emissions are higher. It is simple for anyone with basic maths training and an internet connection to check this, and it is false to claim that “in our lifetime, there has been no correlation between carbon dioxide emissions and temperature” as the Australian’s article does.

Correlation doesn’t prove that one causes the other but this is a good example of how the Australian’s article is inaccurate, relies on falsehoods, and will mislead readers.

Peter Landschützer member picture

Peter Landschützer

Group Leader, Max Planck Institute for Meteorology

The entire article is just a list of inaccurate and false claims made by the author, contradicting the best scientific evidence (e.g. from measurement records) we have today.

Twila Moon member picture

Twila Moon

Research Scientist, University of Colorado, Boulder

This article is a laundry list of falsehoods, misleading examples, and facts taken out of context. It is appalling that such a blatantly false article can be published in any credible news outlet today.

Martin Singh member picture

Martin Singh

Postdoctoral Research fellow, Harvard University

This article is a mixture of misdirection, misleading claims, and outright falsehoods.

The author attempts to paint a picture of current climate change as simply a continuation of natural changes that have occurred in the past. But this neglects the clear evidence that climate change over the last two centuries has been shown to be largely man-made, that it is much more rapid that anything we have seen in the last two thousand years if not longer, and that it is occurring in the context of a globe with more than 7 billion human inhabitants.

The author makes incorrect claims about climate models failing (against what metric?), that climate change cannot be driven by a trace gas (how did we get out of the ice covered state called “snowball Earth”, not to mention the role of carbon dioxide in many examples of climate change over Earth’s history?), that carbon dioxide concentrations were higher at the beginning of the last ice age (they weren’t).

Interspersed with these falsehoods are various long interludes about how carbon dioxide is essential for life and helps plants grow. This doesn’t change the fact that the planet is getting warmer, and it doesn’t change the fact that most studies expect agricultural yields to suffer as the world becomes increasingly warmer in spite of the carbon dioxide fertilisation effect.

The facts are that human activity has increased greenhouse gas concentrations in the atmosphere to levels not seen for close to a million years. Multiple lines of evidence from observations, modelling, and theory shows us that this increase in greenhouse gas concentrations leads to warming of the globe. As this warming continues, it will lead to sea-level rise, changes to rainfall patterns, and, for higher levels of warming, it may render parts of the world essentially uninhabitable for humans without air conditioning. To deny this strong and robust evidence is irresponsible in the extreme.

Katrin Meissner member picture

Katrin Meissner

Professor, University of New South Wales

Virtually every single scientific statement in this article is either misleading or downright wrong. Some statements are almost amusing, such as, “there are no carbon emissions. If there were, we could not see because most carbon is black”.
The Australian should be ashamed of itself. What next? An opinion piece on the flat Earth theory?

Willem Huiskamp member picture

Willem Huiskamp

Postdoctoral research fellow, Potsdam Institute for Climate Impact Research

This article is an absurd collection of non-sequiturs, distortions, and outright falsehoods that have been thoroughly debunked over the past decade. This is obvious propaganda from someone with close financial ties to the fossil fuel industry.

Dan Jones member picture

Dan Jones

Physical Oceanographer, British Antarctic Survey

This article contains a large number of inaccurate and misleading statements. It is not grounded in our understanding of the Earth system.

Mark Eakin member picture

Mark Eakin

Scientist, Coordinator of NOAA’s Coral Reef Watch, National Oceanic and Atmospheric Administration

There are a few points he makes that are true. The other 95% are not. Even those that are true are used to mislead the reader.

Alexis Berg member picture

Alexis Berg

Research Associate, Harvard University

Just like previous pieces by the same author (some of which were already addressed by Climate Feedback), this piece is an unorganized collection of the same old misleading “arguments” from climate change deniers that have been addressed thousands of times before, of which there are too many to summarize here.
It is frankly appalling that any newspaper that would like to retain some credibility would continue to publish such pieces.

Notes:
[1] See the rating guidelines used for article evaluations.
[2] Each evaluation is independent. Scientists’ comments are all published at the same time.

Annotations

The statements quoted below are from the article; comments are from the reviewers (and are lightly edited for clarity).

Pollution by plastics, sulphur and nitrogen gases, particulates and chemicals occurs in developing countries. That’s real pollution.

Willem Huiskamp member picture

Willem Huiskamp

Postdoctoral research fellow, Potsdam Institute for Climate Impact Research

Strangely, Ian Plimer uses the “no true Scotsman” logical fallacy here to imply that because these forms of pollution are an issue, carbon pollution is somehow insignificant.

There are no carbon emissions

Willem Huiskamp member picture

Willem Huiskamp

Postdoctoral research fellow, Potsdam Institute for Climate Impact Research

So absurd as to almost defy comment. Humans are burning coal, petroleum products, and natural gas. Very basic chemistry tells us that a bi-product of this is the creation of carbon dioxide gas.

Peter Landschützer member picture

Peter Landschützer

Group Leader, Max Planck Institute for Meteorology

There are plenty of reliable resources (such as the United Nations Inventory Submissions) that readers can check to find out that there are CO2 emissions. Furthermore, in the last paragraph the author states himself that there are emissions (using China as an example).

If there were [carbon emissions], we could not see because most carbon is black.

Martin Singh member picture

Martin Singh

Postdoctoral Research fellow, Harvard University

Carbon dioxide, the main gas that makes up “carbon emissions”, is colourless and odourless.

Willem Huiskamp member picture

Willem Huiskamp

Postdoctoral research fellow, Potsdam Institute for Climate Impact Research

Most carbon is not black. Black carbon itself results from incomplete combustion of carbon-based fuel such as fossil fuels or biomass. Ironically, it is also a significant contributor to global warming due to its ability to reduce the albedo of ice-covered areas.

Great Barrier Reef bleaching that has really been occurring for hundreds of years

Mark Eakin member picture

Mark Eakin

Scientist, Coordinator of NOAA’s Coral Reef Watch, National Oceanic and Atmospheric Administration

The recent paper that made this claim was some of the worst science to be published in a reputable journal in many years. The authors of all of the datasets they misused wrote the editors calling for the paper to be retracted but the journal decided not to do so. Instead, a rebuttal paper1 provides all the reasons why that paper is wrong and should have been retracted.

Katrin Meissner member picture

Katrin Meissner

Professor, University of New South Wales

The reef’s overall habitat status has been downgraded to “poor” for the first time in this year’s Great Barrier Outlook Report, citing hundreds of peer-reviewed papers. The report considers the condition and outlook of coral reef habitats specifically to be very poor in the northern two-thirds. The assessment clearly states the greatest threat to the Great Barrier Reef’s long-term outlook is climate change.

fraudulent changing of past weather records

Willem Huiskamp member picture

Willem Huiskamp

Postdoctoral research fellow, Potsdam Institute for Climate Impact Research

A lie, referring to the homogenisation of weather records to remove biases. This is nothing more than a conspiracy theory.

For more information on this topic, read our review “NASA did not create global warming by manipulating data

the ignoring of data that shows Pacific islands and the Maldives are growing rather than being inundated

Katrin Meissner member picture

Katrin Meissner

Professor, University of New South Wales

The dynamics of shorelines of low-lying Pacific Islands are complicated and influenced by many local factors. Climate change and associated sea-level change are the underlying trend that will “win” over long time scales. There are many wiggles and local anomalies that, if taken out of context and analysed over short timescales, might hide the overall trend.

For more information on this topic, read our review “Analysis of ‘About Those Non-Disappearing Pacific Islands’

unsubstantiated claims polar ice is melting

Alexis Berg member picture

Alexis Berg

Research Associate, Harvard University

What’s unsubstantiated about polar ice melting? We can literally see Arctic sea ice decrease. Regarding ice caps, there are plenty of studies with different methodologies indicating Greenland and at least parts of Antarctica are losing ice1,2.

Katrin Meissner member picture

Katrin Meissner

Professor, University of New South Wales

This is wrong. Satellite measurements show a decline in Greenland and Antarctica ice mass balances.

We’ve had reefs on planet Earth for 3500 million years. They came and went many times.

Mark Eakin member picture

Mark Eakin

Scientist, Coordinator of NOAA’s Coral Reef Watch, National Oceanic and Atmospheric Administration

Yes, and when they went away during periods of mass extinctions, they were gone for millions of years. Is Mr. Plimer suggesting doing away with the GBR for millions of years is an appropriate price to pay for short-term fossil fuel profits?

The big killer of reefs was because sea level dropped and water temperature decreased

Mark Eakin member picture

Mark Eakin

Scientist, Coordinator of NOAA’s Coral Reef Watch, National Oceanic and Atmospheric Administration

No, reefs were lost during major extinction events caused by high levels of CO2 and runaway warming.

In the past, reefs thrived when water was warmer and there was an elevated carbon dioxide content of the atmosphere.

Peter Landschützer member picture

Peter Landschützer

Group Leader, Max Planck Institute for Meteorology

Marine heatwaves have been a major driver of coral bleaching1.

Katrin Meissner member picture

Katrin Meissner

Professor, University of New South Wales

Today’s reefs are suffering from the fast rates of change. Temperatures are rising too fast to adapt to these changes easily. This results in more frequent and more intense heatwaves and therefore mass bleaching. Much slower warming as in the geological record give ecosystems a chance to adapt. In addition, fast increases in CO2 will reduce carbonate ions in the surface waters which makes the waters more corrosive. If CO2 increases at slower rates, other (slow) feedbacks restore carbonate ions.

Reef material is calcium carbonate, which contains 44 per cent carbon dioxide. Reefs need carbon dioxide; it’s their basic food.

Peter Landschützer member picture

Peter Landschützer

Group Leader, Max Planck Institute for Meteorology

This is not correct. CO2 dissolves in seawater, forming carbonic acid, bicarbonate ion, and carbonate ion. During these reactions, free hydrogen ions are released, which lower the seawater pH and result in ocean acidification. Corals form from calcium carbonate, however, due to the increase of dissolved CO2 in seawater and the resulting increase in hydrogen ion, the dominance of dissolved CO2 species shifts from carbonate ion to bicarbonate ion to maintain chemical equilibrium. This is nicely illustrated in the Bjerrum plot. Therefore, in fact, increasing CO2 levels is not food for corals, but makes the dissolution of CaCO3 more likely.

Bjerrum plot
Source: Wikimedia

We are not living in a period of catastrophic climate change. The past tells us it’s business as usual.

Alexis Berg member picture

Alexis Berg

Research Associate, Harvard University

Absent emission reductions, global mean temperature will likely rise by 3 to 5 °C by 2100 or so. That’s not business-as-usual. It’s a change of geological proportions, almost instantaneous on geological timescales. The last time the Earth was this warm was millions of years ago, and the face of the Earth was markedly different.

Katrin Meissner member picture

Katrin Meissner

Professor, University of New South Wales

Current CO2 concentrations have not been encountered by Earth for at least 3 million years. Last time the climate was in equilibrium with today’s CO2 concentrations, sea levels were much higher (order of magnitude of 10 meters), temperatures were well beyond the Paris Agreement. The rates of change are unprecedented. Current rates of change in CO2 are at least 10 times faster than in any records of past climate.

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

Alexis Berg member picture

Alexis Berg

Research Associate, Harvard University

Literally the whole field of climate science for the last 30 years has shown this.

Katrin Meissner member picture

Katrin Meissner

Professor, University of New South Wales

This is wrong and has been shown in multiple publications, including the IPCC fifth assessment report.

Mark Richardson member picture

Mark Richardson

Research Associate, Colorado State University/NASA JPL

Among other evidence, we have directly measured the amount of heating caused by CO2, using instruments pointed at the sky1. We know the CO2 rise is due to human activity, and this heating is sufficient to explain the observed warming.

Climate models have been around 30 years. They have all failed.

Willem Huiskamp member picture

Willem Huiskamp

Postdoctoral research fellow, Potsdam Institute for Climate Impact Research

See this previous Climate Feedback review for rebuttal.

Alexis Berg member picture

Alexis Berg

Research Associate, Harvard University

Global warming is happening essentially as projected by climate models. The mean warming, the spatial and temporal pattern of that warming, the impact on the water cycle, etc.

Mark Richardson member picture

Mark Richardson

Research Associate, Colorado State University/NASA JPL

The models projected warming, with faster warming at the northern high latitudes. This page includes studies showing that Plimer’s statements are inaccurate.

Modellers assume carbon dioxide drives climate change

Willem Huiskamp member picture

Willem Huiskamp

Postdoctoral research fellow, Potsdam Institute for Climate Impact Research

This is not an assumption. Modellers simply implement the basic laws of physics and chemistry into these numerical models, which then show what we’ve known for over a century—CO2 is a powerful greenhouse gas, which has the potential to change the climate if its concentration in the atmosphere is significantly increased.

Mark Richardson member picture

Mark Richardson

Research Associate, Colorado State University/NASA JPL

This is false.

The models include quantum physics and the transfer of heat and radiation according to the laws of physics. They also include things like changing solar activity. That CO2 is the single largest cause of climate change is an output of the calculations.

The role of the sun and clouds was not considered important by modellers. They are the major drivers for the climate on our planet.

Martin Singh member picture

Martin Singh

Postdoctoral Research fellow, Harvard University

The role of solar variations is considered in climate-model simulations of the past, and projections of future climate change1.

Clouds are considered extremely important by all climate modellers. (See, for example, here.)

Variations in solar irradiance have caused only a very small change to the planet’s overall energy balance over the last century or so. On the other hand, greenhouse gas emissions have caused a much larger change to the planetary energy balance, and this has led to global warming.

Clouds provide an important feedback to climate change, but they cannot reasonably be described as a “driver” of climate change. There must be some other factor that causes the clouds to change. (E.g. changes in the surface temperature owing to greenhouse-gas emissions).

bar chart of radiative forcings
Source: IPCC
Mark Richardson member picture

Mark Richardson

Research Associate, Colorado State University/NASA JPL

This is false, and it’s just as false as the last time Plimer claimed this.

Solar activity and clouds are included in climate models. Here’s a paper from 2006 talking about how clouds are the largest source of uncertainty in the amount of future global warming1.

We emit a trace atmospheric gas called carbon dioxide at a time in planetary history of low atmospheric carbon dioxide.

Willem Huiskamp member picture

Willem Huiskamp

Postdoctoral research fellow, Potsdam Institute for Climate Impact Research

Ian Plimer contradicts himself within the same article, after previously claiming there are no carbon emissions.

Peter Landschützer member picture

Peter Landschützer

Group Leader, Max Planck Institute for Meteorology

Carbon dioxide levels today have exceeded 400 ppm (see measurements at Mauna Loa), whereas ice-core records show that such levels have not existed in the past 800,000 years (see data here).

The geological history of the planet shows major planetary climate changes have never been driven by a trace gas

Martin Singh member picture

Martin Singh

Postdoctoral Research fellow, Harvard University

This is incorrect. Concentrations of CO2 and other trace gases are known to be important for climate change throughout Earth’s history, from the snowball Earth events hundreds of millions of years ago to the ice age cycles of the last million years. (In the latter case, changes in CO2 concentration act as a feedback to changes in Earth’s orbit, but they must be considered in order to explain the observed changes.)

Climate change is normal and continual.

Mark Richardson member picture

Mark Richardson

Research Associate, Colorado State University/NASA JPL

Plimer’s argument is that “climate change is normal and continual” therefore we can’t or shouldn’t do anything about the current climate change that’s being caused by humans.

This is a bit like arguing that radiation is normal and continual, so if there was a risk of someone using nuclear weapons on your city then you shouldn’t try to do anything about that, either.

When cycles overlap, climate change can be rapid and large.

Willem Huiskamp member picture

Willem Huiskamp

Postdoctoral research fellow, Potsdam Institute for Climate Impact Research

There is no evidence of any kind to suggest a combination of natural factors is in any way responsible for the current warming we are experiencing. Current warming is over 100% man-made.

Sporadic events such as supernovas[…] can also change climate.

Willem Huiskamp member picture

Willem Huiskamp

Postdoctoral research fellow, Potsdam Institute for Climate Impact Research

No1.

volcanic eruptions can also change climate.

Willem Huiskamp member picture

Willem Huiskamp

Postdoctoral research fellow, Potsdam Institute for Climate Impact Research

A non-sequitur. Volcanic eruptions cool the climate due to the emission of sulphate aerosols into the upper atmosphere. This is the exact opposite of the current warming we are experiencing.

The main greenhouse gas is water vapour[…]

Peter Landschützer member picture

Peter Landschützer

Group Leader, Max Planck Institute for Meteorology

The IPCC report clearly highlights that CO2 is the most important greenhouse gas regarding the change in anthropogenic radiative forcing since 1750.

bar chart of radiative forcings
Source: IPCC
Willem Huiskamp member picture

Willem Huiskamp

Postdoctoral research fellow, Potsdam Institute for Climate Impact Research

This entire paragraph is a non-sequitur. Water vapour’s role as a greenhouse gas is entirely irrelevant to the effect increasing atmospheric CO2 concentrations are having on Earth’s radiative equilibrium.

Alexis Berg member picture

Alexis Berg

Research Associate, Harvard University

What’s the point of all this? Is this somehow meant to convince readers that climate scientists don’t know about the water cycle and geophysical fluid dynamics? None of this contradicts the fact that increase greenhouse gas concentrations will warm the climate.

Carbon dioxide is a non-condensable atmospheric gas like nitrogen and oxygen

Mark Richardson member picture

Mark Richardson

Research Associate, Colorado State University/NASA JPL

This is why it is more important than water vapour in forcing the climate to change.

If you add a lot of water vapour to the air, it rains out in hours to days, before it can trap enough heat to warm things up. When we burn fossil fuels, the amount of CO2 in the air will remain higher for at least 100 years.

It sticks around for long enough to drive long-term changes in the climate.

Martin Singh member picture

Martin Singh

Postdoctoral Research fellow, Harvard University

Except that, unlike nitrogen and oxygen, carbon dioxide’s molecular structure allows it to absorb infrared radiation, thereby making it a greenhouse gas.

Without carbon dioxide, all life on Earth would die

Willem Huiskamp member picture

Willem Huiskamp

Postdoctoral research fellow, Potsdam Institute for Climate Impact Research

And without water, humans would die but we still tend to avoid living under water.

Mark Eakin member picture

Mark Eakin

Scientist, Coordinator of NOAA’s Coral Reef Watch, National Oceanic and Atmospheric Administration

This is one of the few things the author gets right. Unfortunately, he forgets the importance of “all things in moderation”.

Mark Richardson member picture

Mark Richardson

Research Associate, Colorado State University/NASA JPL

This is ridiculous alarmism and irrelevant.

No one proposes removing all carbon dioxide from the atmosphere. It’s just that with more CO2 in the atmosphere, Earth gets hotter and there are consequences of that.

Plants need almost three times today’s carbon dioxide content of the atmosphere to thrive. For decades horticulturalists have pumped carbon dioxide into glasshouses to increase yields.

Alexis Berg member picture

Alexis Berg

Research Associate, Harvard University

Yes but in the natural world increased CO2 concentration is associated with changes in climate that may be detrimental to plants (warming, changes in precipitation, etc.). In fact, there’s growing evidence that while increasing CO2 has indeed been fertilizing vegetation globally in the last few decades, climate change is starting to negatively impact it.

[For more information on this topic, read our review “In CNN interview, William Happer misleads about the impact of rising carbon dioxide on plant life”]

In the past, warming has never been a threat to life on Earth. Why should it be now?

Alexis Berg member picture

Alexis Berg

Research Associate, Harvard University

Maybe not slow, progressive warming. Abrupt warming probably is. There are past examples of that. Besides, the worry is not about “all life on Earth” (strawman argument): it’s first and foremost about human civilization, which has developed over the last 10,000 years in a very stable climate. A sedentary humanity with 8 billion people is likely going to suffer from a geological-scale +4 °C planetary warming within a couple centuries…

Mark Richardson member picture

Mark Richardson

Research Associate, Colorado State University/NASA JPL

There are plenty of studies showing mass extinction events during past warming. Like during the Paleocene-Eocene Thermal Maximum, where warming was slower than today1,2,3. The warming was eventually larger than we’ve seen so far, but it’s up to our policy choices as to whether we want to make things hotter than that extinction event or not.

Mark Eakin member picture

Mark Eakin

Scientist, Coordinator of NOAA’s Coral Reef Watch, National Oceanic and Atmospheric Administration

No, in fact, past extinction of corals occurred at times of high CO2 and runaway warming.

if we halved today’s atmospheric carbon dioxide content, all life would die.

Peter Landschützer member picture

Peter Landschützer

Group Leader, Max Planck Institute for Meteorology

This claim is contradicted by measurements: Ice core records show several periods within the past 800,000 years (see again here) where the carbon dioxide content in the atmosphere was about 200ppm, whereas today we have reached 400ppm (or 0.04% as the author writes below).

Our bodies contain carbon compounds. If we were so passionately concerned about our carbon footprint, then the best thing to do is to expire.

Mark Richardson member picture

Mark Richardson

Research Associate, Colorado State University/NASA JPL

This is false. The natural carbon cycle keeps atmospheric CO2 amounts approximately in balance.

The changes in atmospheric CO2 are almost entirely due to releasing trapped carbon into the air. The single biggest contributor is digging up carbon that’s trapped in fossil fuels and then burning them to release the CO2. A secondary one is releasing carbon trapped in things like forests and peat.

Willem Huiskamp member picture

Willem Huiskamp

Postdoctoral research fellow, Potsdam Institute for Climate Impact Research

This is incorrect unless our bodies were sequestered into an isolated component of the carbon cycle such as buried fossil fuel reserves. Otherwise, carbon is cycled regularly between the different components of the carbon cycle, while as a whole the system is in relative equilibrium. This only changes when we liberate isolated reserves of carbon and add them to the more “active” pools, as we are doing with the extraction and combustion of fossil fuels.

In our lifetime, there has been no correlation between carbon dioxide emissions and temperature

Mark Richardson member picture

Mark Richardson

Research Associate, Colorado State University/NASA JPL

This is false.

Our total emissions correlate strongly with temperature, just as expected.

The CDIAC global emissions data are only available until the end of 2014, but the total emissions correlate with global temperature. Over the last 50 years of the datasets the correlation coefficient is 0.93 (where 0 means no correlation and 1 means perfect correlation).

after a natural orbitally driven warming, atmospheric carbon dioxide content increases 800 years later

Katrin Meissner member picture

Katrin Meissner

Professor, University of New South Wales

During natural climate variability, temperature and CO2 are tightly linked, with feedbacks going both ways. Even if in some cases temperature increased before CO2, the majority of warming occurred after the increase in CO2.

Rather than atmos­pheric carbon dioxide driving temperature, it is the opposite.

Martin Singh member picture

Martin Singh

Postdoctoral Research fellow, Harvard University

The increase in atmospheric carbon dioxide concentration observed over the last century or so is entirely due to human activity. In fact, the natural world is currently absorbing carbon dioxide from the atmosphere, partly offsetting our emissions. An important question in climate science is the extent to which the natural world (oceans and biosphere) can continue to partially offset our emissions in the future, or if the natural world will become a source of carbon emissions,

Geology shows us again there is no correlation between atmospheric carbon dioxide and temperature

Katrin Meissner member picture

Katrin Meissner

Professor, University of New South Wales

Thats is wrong. Ice cores show a tight correlation between temperature and greenhouse gas concentrations.

plot of ice core data
Proxy records of temperature (blue), CO2 concentration (green), and dust content (red) from an Antarctic ice core.
Source: Wikimedia

Each of the six major past ice ages began when the atmospheric carbon dioxide content was far higher than at present.

Martin Singh member picture

Martin Singh

Postdoctoral Research fellow, Harvard University

No, the carbon dioxide concentration has not been higher for at least 800,000 years. There have been at least six ice ages in that time.

See here.

In the past decade China has increased its carbon dioxide emissions by 53 per cent, 12 times Australia’s total carbon dioxide output of 1.3 per cent of the global total.

Katrin Meissner member picture

Katrin Meissner

Professor, University of New South Wales

The 1.3% become much larger if we look at per capita emissions. And much much larger when we include emissions from exported coal from Australia. Following that logic, I suggest we all stop paying taxes, because our individual contribution is much less than 1.3% and surely would not make a difference?

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