“We need to be very careful about comparisons.”
“While a new ice age may be expected in the next few thousand years, there is no reason to expect it soon. As shown by the extreme right hand end of the carbon dioxide graph, we are now in uncharted territory.”
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The debates around climate change are fascinating – and are being conducted in this part of the world too.
A correspondent has just commented on a recent posting – where the appearance of flowers in the Sid Valley was compared using the weather data from 1865-71 and 2017-20:
Sidmouth’s changing climate – Vision Group for Sidmouth
“I think we need to be very careful about comparisons. When the readings from 1861 were taken we were still in the ‘little ice age’”
Little Ice Age | geochronology | Britannica
And indeed, as also pointed out, it was much warmer in Roman times.
This long-view is from 2016:
Using Patterns of Recurring Climate Cycles to Predict Future Climate Changes
The Pacific Decadal Oscillation (PDO) shows excellent correlation with climate changes during the past century—two periods of global warming and three periods of global cooling exactly match switches in PDO. In 2000, I projected these cyclic patterns into the future and predicted 25–30 years of global cooling, and over the past 15 years, the climate has cooled slightly. As we enter a Solar Minimum strongly resembling the Dalton Minimum when strong global cooling occurred, we can expect further cooling.
Using Patterns of Recurring Climate Cycles to Predict Future Climate Changes – ScienceDirect
These webpages are particularly interesting – as they covers the 1865-71 period:
Weather in History 1850 to 1899 AD
There are clearly ‘natural’ patterns of warming and cooling of the atmosphere:
Hasn’t Earth warmed and cooled naturally throughout history? | NOAA Climate.gov
The issue, however, is whether the current ‘warming’ has been exacerbated by human activity: in other words, whether this is ‘anthropogenic global warming’ happening:
Human fingerprints on climate change rule out natural cycles
Global warming refers to the long-term warming of global temperature since the 1850s. The cause of global warming has been investigated by many scientists, who have summarized their finding in multiple assessment reports by the Intergovernmental Panel on Climate Change (IPCC). The only plausible mechanism of global warming is a planetary energy imbalance, with our climate system building up heat. This and the observed fingerprints left on global warming confirm the dominant role of human activities.
Human fingerprints on climate change rule out natural cycles | scepticalscience.com
Fact check: Is global warming merely a natural cycle?
Benjamin Cook, a climate scientist at the NASA Goddard Institute for Space Studies, said back in the late 20th century, when researchers started to look for answers to explain the warming trend, they examined different factors including greenhouse gases, solar energy, ocean circulation and volcanic activity. “Only the greenhouse gas emissions from fossil fuels and industrialization gave us a prediction that lines up with the warming we’re seeing,” Cook told DW. He said the scientific community is as confident in human-caused climate change today as in the understanding of the theory of gravity. “There are uncertainties and nuances to discuss in climate science,” said Cook. “But the one thing pretty much every scientist agrees upon today is that the warming we’re seeing is driven by burning fossil fuels.”
To finish in the Sid Valley, Prof Brian Golding, formerly of the Met Office and Sidmouth resident, has put this explanation together – which has several helpful graphs:
A history of climate change: Prof Brian Golding – Vision Group for Sidmouth