It is no use arguing with the anthropogenic global warming/climate change sceptics represented in previous Sunday Mail letters’ page writers such as “Douglas” and Geoffrey Evans, but despite denials there is a long-term warming trend which has continued in 2018, with the average global temperature set to be the fourth highest on record.
The 20 warmest years on record have been in the past 22 years, with the top four in the past four years, according to the World Meteorological Organisation. To quote professor Katharine Hayhoe, from at Texas Tech University and director of its Climate Science Centre: “If you look at natural factors, every single natural factor either says there will be no change or we should actually be cooling right now. If we look at the sun, if we look at volcanoes, if we look at orbital forcing, and if we look at natural cycles, none of them can explain the warming. In fact, we should actually be getting cooler today.”
The real big issue is the level of CO2. It has fluctuated between about 180 – 280 ppm (parts per million) over the past 420,000 years, and very closely moves with temperature. Now the level has risen to 400 ppm, a 40 per cent increase. This correlates with our emissions from burning fossil fuels, reduction of forest cover, and other factors. This increase quite simply cannot be effectively absorbed by the natural systems of the planet.
Yes, we had warm periods before, but the Mediaeval warm period (frequently cited by deniers) was limited in scope to Europe, possibly because of changes in the Gulf stream, and the warming recorded was less than we are seeing today. As for the chart generated from ice cores from Greenland concerning Younger Dryas which accompanied a recent letter from Geoffrey Evans, that too may well be rather local, as cores in Antarctica show warming. Today, the world-wide trend is for warming.
About 97 per cent of climate scientists share the consensus that anthropogenic global warming and the consequent climate change is real: the consensus isn’t proof of human-caused climate change. Instead, the consensus has emerged from the evidence collected and analysed for over 150 years by thousands of scientists around the globe, in particular since the 1930s when climate science took-off.
Here, critically, evidence of global warming was only found after the theory by which such global warming might occur had been developed and at a time when no one stood to make money from it, not that climate change scientists do, anyway.
In 1824 Jean Baptiste Joseph Fourier theorised that solar radiation alone was insufficient to account for the general temperature of the earth and something was trapping heat.
In 1859 John Tyndall established by laboratory experimentation that CO2 and water vapour acted as greenhouse gases, trapping heat.
In 1896 Svante Arrhenius reasoned that CO2 was the main regulator and that changes in the amount of CO2 in the atmosphere would, if negative, result in cooling or, if positive, in warming. Indeed, he predicted that that if you halved the amount of atmospheric carbon dioxide, the temperature of Europe could drop by as much as 4-5°C, while if the amount of CO2 doubled one would have 5-6°C of warming as a globally averaged figure. Knut Ångström disputed this but his experiments have since been found to flawed.
In 1931, American physicist EO Hulburt came up with a figure of around 4°C of warming, essentially confirming and adding to the work of Arrhenius.
In 1938 an English engineer, Guy Stewart Callendar, looked at the issue, where many people, looking at weather stories from the past, had been saying that a warming trend was underway. When Callendar compiled measurements of temperatures from the 19th century on, he found they were right: average globally reported temperature was increasing, and, after evaluating old measurements of atmospheric CO2 concentrations, he concluded that over the previous hundred years the concentration of the gas had increased by about 10 per cent. Callendar concluded that this rise could, based upon established science, explain the observed warming.
That science has never been properly disproved. Rather it has been improved upon and Al Gore, so often the demon cited by climate change deniers as promoting anthropogenic climate change, would not be born for another 10 years!
The true conspiracy in climate change is how major petrochemical companies have known and privately admitted that anthropogenic global warming (with attendant climate consequences) has existed for some years but have poured millions into lobbying against measures designed to protect us from the consequences. For example, over a 16-year period fossil fuel interests and big petrochem in the USA spent about ten times as much lobbying as opposed to environmental groups.
Why? Because many of the steps needed to try reduce the effects climate change will hurt their profits.
Looking at the science of climate change denial has been found to be the true junk science.
A 2016 paper (Freely available) “Learning from mistakes in climate research” by Rasmus E Benestad, Dana Nuccitelli, Stephan Lewandowsky, Katharine Hayhoe, Hans Olav Hygen, Rob van Dorland and John Cook looked at a selection of papers rejecting anthropogenic global warming. An analytical tool was developed to replicate and test the results and methods used in these studies.
That replication revealed a number of methodological flaws, including missing contextual information or ignoring information that does not fit the conclusions. In many cases, shortcomings were due to insufficient model evaluation, leading to results that were an artefact of a particular experimental setup. Other typical weaknesses found included false dichotomies, inappropriate statistical methods, or basing conclusions on misconceived or incomplete physics. Part of the problem is flaws in the peer review process.
So take it from the 97 per cent of competent climate change scientists. Anthropogenic global warming and consequent climate change is real, and ask who is paying the scientists that deny climate change.
Trevor JS Elliston, Limassol