50 reasons why global warming isn't natural
Michael Le Page, features editor
A British newspaper today published a list of "100 reasons why global warming is natural".
Here we take a quick look at the first 50 of their claims - and debunk each one.
1) There is "no real scientific proof" that the current warming is caused by the rise of greenhouse gases from man's activity.
Technically, proof exists only in mathematics, not in science. Whatever terminology you choose to use, however, there is overwhelming evidence that the current warming is caused by the rise in greenhouse gases due to human activities.
2) Man-made carbon dioxide emissions throughout human history constitute less than 0.00022 per cent of the total naturally emitted from the mantle of the Earth during geological history.
Misleading comparison. Since the industrial age began human emissions are far higher than volcanic emissions.
3) Warmer periods of the Earth's history came around 800 years before rises in CO2 levels.
In the past 3 million years changing levels of sunshine triggered and ended the ice ages. Carbon dioxide was a feedback that increased warming, rather than the initial cause. In the more distant past, several warming episodes were directly triggered by CO2.
4) After world war 2, there was a huge surge in recorded CO2 emissions but global temperatures fell for four decades after 1940.
In fact, temperatures fell during the 1940s and then remained roughly level until the late 1970s. The fall was partly due to high levels of pollutants such as sulphur dioxide counteracting the warming effect.
5) Throughout the Earth's history, temperatures have often been warmer than now and CO2 levels have often been higher - more than 10 times as high.
Which shows that higher CO2 means higher temperatures, taking into account the fact that the sun was cooler in the past. The crucial point is that civilisation is adapted to 20th century temperatures.
6) Significant changes in climate have continually occurred throughout geologic time.
Yes. And sea level has been up to 70 metres higher during warm periods. If that happens again, there'll be no more London or New York.
7) The 0.7 °C increase in the average global temperature over the past hundred years is entirely consistent with well-established, long-term, natural climate trends.
Wrong. The rapid warming since the late 1970s has occurred even though other factors that can warm the planet, such as the sun's intensity, have remained constant.
8) The IPCC theory is driven by just 60 scientists and favourable reviewers, not the 4000 usually cited.
Untrue, as even the briefest look at the scientific literature can establish.
9) Leaked e-mails from British climate scientists - in a scandal known as "climategate" - suggest that that has been manipulated to exaggerate global warming
Nothing in the emails undermines any of the key scientific conclusions. Independent groups have come to the same conclusions.
10) A large body of scientific research suggests that the sun is responsible for the greater share of climate change during the past hundred years.
The sun may have contributed to the warming in the first part of the 20th century but it has not caused the rapid warming since the late 1970s.
11) Politicians and activists claim rising sea levels are a direct cause of global warming, but sea levels have been increasing steadily since the last ice age 10,000 years ago.
Wrong. Sea level rose very rapidly as the North American ice sheet melted after the last ice age but levelled off and has been nearly stable for the past 2000 years or so. Now it is starting to rise rapidly again.
12) Philip Stott, emeritus professor of biogeography at the School of Oriental and African Studies in London says climate change is too complicated to be caused by just one factor, whether CO2 or clouds.
He is right. All sorts of factors affect climate, even the lead in petrol. However, the recent warming is mostly due to rising greenhouse gases, and if we pump out more CO2 it will get even hotter.
13) Peter Lilley MP said last month that "fewer people in Britain than in any other country believe in the importance of global warming. That is despite the fact that our government and our political class - predominantly - are more committed to it than their counterparts in any other country in the world".
Irrelevant and incorrect on all counts.
14) In pursuit of the global warming rhetoric, wind farms will do very little to nothing to reduce CO2 emissions.
There are arguments over how much wind power can contribute, but there is no doubt they are already helping reduce emissions in many countries.
15) Professor Plimer, professor of geology and earth sciences at the University of Adelaide, stated that the idea of taking a single trace gas in the atmosphere, accusing it and finding it guilty of total responsibility for climate change, is an "absurdity".
See (1). And note that Plimer is a geologist, not a climatologist.
16) A Harvard University astrophysicist and geophysicist, Willie Soon, said he is "embarrassed and puzzled" by the shallow science in papers that support the proposition that the Earth faces a climate crisis caused by global warming.
Many scientists think Soon should be embarrassed by some of the papers he has published.
17) The science of what determines the Earth's temperature is in fact far from settled or understood.
There are still lots of details to fill in but the big picture is increasingly clear. The uncertainties that do exist swing both ways: there could be more warming than predicted.
18) Despite activist concerns over CO2 levels, CO2 is a minor greenhouse gas, unlike water vapour, which is tied to climate concerns, and which we can't even pretend to control.
Water vapour is a feedback, not a cause of warming. The amount of water in the atmosphere depends on temperature; any excess rains out within days.
19) A petition by scientists trying to tell the world that the political and media portrayal of global warming is false was put forward in the Heidelberg Appeal in 1992. Today, more than 4000 signatories, including 72 Nobel prizewinners, from 106 countries have signed it.
That's not what the Heidelberg Appeal really said, and 1992 was a long time ago.
20) It is claimed the average global temperature increased at a dangerously fast rate in the 20th century but the recent rate of average global temperature rise has been between 1 and 2 °C per century - within natural rates.
Incorrect. Over the past 1000 years temperature has never changed nearly as fast.
21) Professor Zbigniew Jaworowski, chairman of the scientific council of the Central Laboratory for Radiological Protection in Warsaw, Poland, says the Earth's temperature has more to do with cloud cover and water vapour than CO2 concentration in the atmosphere.
See (18). And why believe someone whose work was rejected by the scientific community?
22) There is strong evidence from solar studies which suggests that the Earth's current temperature stasis will be followed by climatic cooling over the next few decades.
The Earth is still warming and even if the sun's intensity does fall, it will not outweigh the effect of rising greenhouse gases.
23) It is a myth that receding glaciers are proof of global warming as glaciers have been receding and growing cyclically for many centuries.
Incorrect. The current retreat is unprecendented.
24) It is a falsehood that the Earth's poles are warming because that is natural variation and while the western Arctic may be getting somewhat warmer we also see that the Eastern Arctic and Greenland are getting colder.
Illogical and incorrect. Warming is warming whatever causes it. And all parts of the Arctic are warmer compared with the average from 1951 to 1980. The extent of the warming is contributing to the rapidly shrinking in the extent of sea ice cover during summer.
25) The Intergovernmental Panel on Climate Change claims climate-driven "impacts on biodiversity are significant and of key relevance", but those claims are simply not supported by scientific research.
There is already clear evidence that the distributions of many species are changing as the planet warms (PDF). If it gets much warmer, some will have nowhere to go.
26) The IPCC threat of climate change to the world's species does not make sense as wild species are at least 1 million years old, which means they have all been through hundreds of climate cycles.
Many species are less than 1 million years old. In any case, during the past 3 million years, the Earth has got a lot colder than it is now during ice ages but never much hotter.
27) Research goes strongly against claims that CO2-induced global warming would cause catastrophic disintegration of the Greenland and Antarctic ice sheets.
Depends on what timescale you are talking about. Scientists differ on how quickly they think the ice sheets will melt, but studies of warm periods leave no doubt that if the temperature gets much higher and stays higher, all the ice sheets will melt completely after several centuries or millennia, causing sea level to rise by 70 metres.
28) Despite activist concerns over CO2 levels, rising CO2 levels are our best hope of raising crop yields to feed an ever-growing population.
Higher CO2 levels do boost growth of some plants, but only if there's enough water throughout the growing season and the temperature is appropriate for particular plants. Overall, climate change is expected to reduce yields once the temperature rise exceeds 3 °C.
29) The biggest climate change ever experienced on Earth took place around 700 million years ago.
So what?
30) The slight increase in temperature which has been observed since 1900 is entirely consistent with well-established, long-term natural climate cycles.
Repetitive and incorrect. See (10).
31) Despite activist concerns over CO2 levels, rising CO2 levels of some so-called "greenhouse gases" may be contributing to higher oxygen levels and global cooling, not warming.
Burning fossil fuels produces CO2 and consumes oxygen, and thus lowers oxygen levels, though the decrease is too tiny to matter.
32) Accurate satellite, balloon and mountain-top observations made over the past three decades have not shown any significant change in the long-term rate of increase in global temperatures.
The rate of increase is in line with predictions.
33) Today's CO2 concentration of around 385 ppm is very low compared with most of the Earth's history - we actually live in a carbon-deficient atmosphere.
And when CO2 levels were higher there were no ice sheets and sea levels were 70 metres higher. Plus, the sun was cooler in the past.
34) It is a myth that CO2 is the most common greenhouse gas because greenhouse gases form about 3 per cent of the atmosphere by volume, and CO2 constitutes about 0.037 per cent of the atmosphere.
You can only get close to the 3 per cent figure by counting water vapour, which as we have already said is a feedback not a cause.
35) It is a myth that computer models verify that CO2 increases will cause significant global warming because computer models can be made to "verify" anything.
No, they can't, because climate models are based on the physical laws that apply in the real world. In any case, the crucial evidence that CO2 warms the planet comes from physics and chemistry, not from general climate models.
36) There is no scientific or statistical evidence whatsoever that global warming will cause more storms and other weather extremes.
Incorrect. For instance, while there is much uncertainty in this area, there is growing evidence that hurricanes will get stronger, though there may not be more of them.
37) One statement deleted from a UN report in 1996 stated that "none of the studies cited above has shown clear evidence that we can attribute the observed climate changes to increases in greenhouse gases".
Meaningless taken out of context, without knowing what studies the statement was referring to.
38) The world "warmed" by 0.07 +/- 0.07 °C from 1999 to 2008, not the 0.20 °C expected by the IPCC.
Actually temperature rose 0.19 ºC, but global warming does not mean natural variation goes away. Periods of cooling are still to be expected.
39) The IPCC says "it is likely that future tropical cyclones (typhoons and hurricanes) will become more intense" but there has been no increase in the intensity or frequency of tropical cyclones globally.
Incorrect. Some studies have found an increase.
:darwin
