No climate event of the last 2,000 years looks like humanity’s
Warm or cool periods you may have heard of were regional affairs
https://arstechnica.com/science/2019/07/the-only-global-climate-event-of-last-2000-years-was-ours/
Cheers,
Bart
Thanks for the link, Bart. This report seems to be consistent with Professor Stephen Schneider's recommendation that climate scientists should be prepared to sacrifice some of the the truth in order to be politically effective.
I had a look at the abstract of the report in Nature.com, and discovered the headline is:
"No evidence for globally coherent warm and cold periods over the preindustrial Common Era"'No evidence' is not 'evidence'. Didn't you mention in a previous post that temperature records prior to the 1850's are not as accurate as current records because they rely upon proxies, such as ice cores, tree rings and sediment analysis?
Another comment on the report:
"Raphael Neukom and colleagues assess the global patterns of climate variability during the Common Era, using data compiled from nearly 700 proxy records of temperature changes. In their Nature paper, they report that before the 20th century, climate epochs did not occur simultaneously across the globe as previously thought."Less than 700 proxy records to examine the degree of global consistency of climate changes during the past 2,000 years, compared with the hundreds of thousands, if not millions, of instrumental records we have for the 100 years or so since industrialisation!! Wow!! It's no wonder that Climatology is often described as a 'soft' science.
The other point I take issue with is, 'as previously thought'. The global extent of the Roman Warm Period, the MWP, and the LIA have always been contentious due to a lack of sufficiently accurate and widespread data.
The Michael Mann 'Hockey Stick' graph which seemed to obliterate the existence of the MWP as a global event, was severely criticised because a number of scientific studies already existed at the time, at least implying that the MWP was global. The issue led to a court case in which Mann struggled to defend his reputation.
Another issue which seems like an excellent example of a 'strawman argument', is the following comment.
“Climate has changed without humans before, so humans can’t be changing it now” is not a logically valid argument, FYI. It's the equivalent to arguing that we can't cause forest fires, since they occurred before we were around.
I've never heard any such argument from the skeptics. It's understood, at least by the skeptics whose opinions I've come across, that there are numerous influences on climate, which are too complex to accurately quantify. Only a fool would claim that humanity's activities have no influence on climate.
I would argue that it's a universal truth that nothing is permanent, although the degree of permanency varies enormously depending on the nature of the subject. Most complex systems are constantly subject to change. All life- forms change as they age, and eventually die. Buildings and infrastructure gradually decay, mountains gradually erode and new mountains are gradually created due to volcanic eruptions and plate tectonics, and so on.
Everything is subject to a process of 'cause and effect'.
I would say it's a reasonable hypothesis that the current warming might be more homogenous and synchronous, globally, than certain previous warm periods, due to mankind's increased activities in general, including, in particular, changing the environment by cutting down huge areas of forests, building cities, suburbs and roads world-wide, which create an Urban Heat Island effect, and ceasing to return our natural waste products such as crop residue, faeces and urine, back to the soil.
It's only reasonable to assume that emissions of CO2 due to the burning of fossil fuels must contribute at least something to the current warming, even though water vapour is by far a more significant greenhouse gas in total.
What concerns me about the demonisation of CO2 is the disregard, and even denial of the benefits of increased CO2 levels, which can be demonstrated in a 'hard science' way through repeated experiments, growing plants in an environment with increased CO2 levels, and observing the results.
Since we know with certainty that CO2 is essential for all life, and that most plants thrive on elevated levels, why not exploit the benefits to improve the environment, instead of ignoring the benefits?
The environment can be improved through reforestation. Newly planted forests will grow more quickly in elevated levels of CO2 and the increased precipitation that inevitably results from warming will also help.
It's also well established that modern agriculture tends to degrade our soils, reduces the biodiversity of the soil, and reduces the carbon content of the soil.
Changing this system for the better would potentially happen more quickly and more profitably with elevated CO2 levels. Instead of trying to eliminate CO2 emissions, why not sequester the carbon in the soil to restore the natural biodiversity of the soil, as well as continuing with the development of alternative forms of energy such as solar power, which would obviously be of great benefit as fossil fuel supplies dwindled and became more expensive, regardless of concerns about climate change?
