Abrupt changes in global temperatures are commonplace throughout the climate record. Movements as high as 5-10°C have been recorded over periods of just a few years, and these compare with the 1.1°C warming seen today that dates back to the early 19th century. Of course, these changes are well known, but they have been downplayed of late as Net Zero political activists proclaim that the climate is breaking down owing to human emissions.
Professor Mark Maslin is a regular broadcaster on the so-called climate emergency. In October 2021, he tweeted: “The climate disaster is here. Earth is already becoming unliveable.” In 2019, he responded to an Australian think tank report stating that climate change could bring about the end of civilisation as we know it, by stating: “Maybe, just may[be], it is time for our politicians to be worried and start to act to avoid the scenarios painted so vividly.” In 2018, Maslin was one of a number of influential eco-activists who signed a letter to the Guardian saying that they would no longer “lend their credibility” by debating climate change scepticism.
In 1999, his language was more measured. In a paper he co-wrote on “sudden climate transitions”, he said: “All the evidence indicates that most long-term climate change occurs in sudden jumps rather than incremental change… the tendency of climate to change relatively suddenly has been one of the most surprising outcomes of the study of earth history, specifically the last 150,000 years.” He went on to add that some, and possibly most, large climate changes involving movements of several degrees centigrade occurred at most on a timescale of a few centuries, sometimes decades, “and perhaps even a few years”.
On the basis of what he said then, it could be argued that the recent rise over nearly 200 years of just over 1°C from a prior 500 year cooling period, is hardly evidence of a climate emergency. Let us examine the record further.
The recent Watt’s Up With That? essay winner, “Is there really a climate crisis?” reproduced the above graph above from the Utah Geological Survey showing the cycle of glacial and interglacial cycles. The temperature change on the left refers to Antarctica ice cores and not global averages. Dramatic averaged changes up to 20°F (11°C) can been seen across the last 450,000 years. As the essay noted, the current inter-glacial is about 8°F (4.4°C) degrees cooler than the maximum temperature of the one preceding it.
This graph was presented by the German broadcaster ARD in 2013 and uses scientific data. It clearly shows the periods of warming and cooling that have occurred in the recent past, following the lifting of the last glacial period 11,000 years ago. A significant warming occurred 8,000 years ago, with temperatures much higher than today. Temperatures then dropped 3°C, only to rise by a similar amount in the subsequent significant warm period. The Roman warming saw grapes being grown in England as far north as Lincolnshire, while the Medieval warming was followed by the little ice age, when the River Thames froze during winter. The current – some might say, welcome – warming might have a little way to go, but it seems to lack the rate of ascent seen in the first two examples.
It is likely that our old friend Professor Maslin might disagree. Back in 1999, he was working out of the Geography Department at Imperial College. Now promoted to Professor of Earth Systems Science, he suggests we may have kicked off the sixth mass extinction on Earth, “and the global climate is warming so fast we have delayed the next ice age”. In his view, the Anthropocene – activist-speak for the renamed Holocene era – began with European colonisation and mass slavery. The origins of racism and climate emergency “share common causes”, he thinks.
Let us return to the science. Over the last few decades, scientists have examined ice core records in the Arctic and Antarctica and found numerous examples of sharp, short-term temperature change. No substantive evidence has been found linking temperature change to varying levels of carbon dioxide in the atmosphere. The No Tricks Zone climate site has compiled a number of significant changes. Numerous citations are listed here. For instance, Dr Ruza Ivanovic of Leeds University records a time 14,500 years ago when temperatures in the Northern hemisphere rose by 4-5°C in just a few decades.
A number of scientists have pointed to an abrupt global multiple degree cooling and warming period that occurred about 8,200 years ago over 150 years. Dr. Takuro Kobashi examined the paleoclimatic records and found a drop around 3°C within two decades, followed by a similar rise over 70 years. During this period, it is noted CO2 levels remained the same. Historian Dr. Seren Griffiths of Manchester Met University reported that the event was first identified in Greenland ice cores, but subsequently noted in multiple proxies across Europe. Another abrupt cooling period is said to have occurred about 4,000 years ago.
Looking further back into the geological record, temperatures rose dozens of times by up to 10°C within decades between 80,000 and 20,000 years ago. These are known as DO events and are named after the paleoclimatologists Willi Dansgaard and Hans Oeschger. During the last glacial, temperatures would rise by multiple degrees about every 1,500 years. Physics professor Zhi-Gang Shao of South China Normal University, states that DO events are part of the natural variability and are not externally triggered.
Dramatic temperature rises and falls are common in the climate record. Professor Emeritus of Biogeography Philip Stott at the School of Oriental and African Studies is a noted climate sceptic. He argues that the idea of climate stability is an oxymoron:
Opponents of global warming are often snidely referred to as ‘climate change deniers’; precisely the opposite is true. Those who question the myth of global warming are passionate believers in climate change – it is the global warmers who deny that climate change is the norm.
Chris Morrison is the Daily Sceptic’s Environment Editor