Archives de catégorie : climate-debate

Is Global Warming The Greatest Scientific Fraud In History?

by G.K. Mitchell, Aug 19, 202 in ClimateChangeDispatch


In its seminal report in 1990, the U.N. IPCC stated that “at the then current rate of world emissions of CO2, the global mean temperature would likely increase by 1°C by 2025.

This statement formed the basis for the hypothesis that anthropogenic (man-made) global warmingresulted from the increased concentration of CO2 in the Earth’s lower atmosphere resulting from man-made activities.

Central to the hypothesis was that the temperature of the lower troposphere would increase as the concentration of CO2 in the troposphere increased.

Therefore, in its 1990 report, the U.N. IPCC established a direct linkage between the concentration of CO2 in the atmosphere and the temperature of the lower troposphere.

The scientific method of inquiry has guided scientific research and investigation for over 400 years. In summary, the scientific method requires that a researcher observe a phenomenon, postulate a hypothesis for the cause of the phenomenon, and then conduct experiments or scientific investigations to falsify the hypothesis.

In adherence to the scientific method, a climate scientist who thinks that man has caused global warming should develop a complex hypothesis as follows:

  1. Global warming has occurred; that is, the temperature of the world’s oceans, landmass, and relevant atmosphere has risen during the period under investigation by a statistically significant amount.

  2. Man’s activities are responsible for the global warming that has occurred.

  3. The extent to which global warming has occurred, or is reasonably projected to occur in the future, will adversely affect life on Earth.

If any of the conjectures in the complex hypothesis above are found to be invalid, the complex hypothesis is determined to be falsified and either discarded or modified.

Europe wildfires: Are they linked to climate change?–NO!!!

by P. Homewood, Aug 15, 2022 in NotaLotofPeopleKnowThat


The BBC would like you to think so, with statements like these:

So far this year, the amount of land burnt by fires across the European Union is more than three times greater than what you would expect by the middle of July.

Almost 346,000 hectares (1,370 sq miles) of land have been recorded as burnt (as of 16 July), according to the European Forest Fire Information System (EFFIS).

Much of Western Europe has been hit by a record-breaking heatwave, which substantially increases the risk of fires….

“Heatwaves and droughts are exacerbated by climate change and are absolutely the defining factor in years with massive wildfire outbreaks, like the present one,” Dr Jones says….

“But we definitely see trends in fire weather risk because of climate change.

“The risk is higher in the Mediterranean region than the rest of Europe.”

Studies show increasing fire risk for central and southern regions of Europe over the past couple of decades.

Yet tucked away in the same article is this graph which proves all of these have no basis in fact:

Activist Scientists Have Now Officially Changed A -0.5°C Global Cooling Trend Into A Warming Trend

by K. Richard, Aug 15, 2022 in NotricksZone


Back in the days when data manipulation was still strictly forbidden, scientists reported the globe cooled significantly for decades even as CO₂ concentrations increased.

The global cooling amplitude was -0.5°C from 1960-1965, and 1976 was reported to be the coldest year of any year measured since 1958 (Angell and Korshover, 1978).

Today these recorded 1960-1965 and 1958-1963 cooling trends have been fully erased and replaced with a slight warming or pause.

Apocalyptic Versus Post-Apocalyptic Climate Politics

by J. Curry, Aug 11, 2022 in WUWT


From Climate Etc.

The Inflation Reduction Act that has passed in the US Senate contains a healthy dose of funding for energy and climate initiatives.  There is much discussion as to why this bill looks like it will pass, when previous climate bills (carbon tax, carbon cap and trade) failed.

The Senate bill includes billions of dollars in tax credits and subsidies for clean energy and electric vehicles. In addition to renewable-energy funding, there is also commitment to federal oil and gas expansion, albeit with fines for excessive methane leakage. The bill includes climate resiliency funding for tribal governments and Native Hawaiians and other disadvantaged areas disproportionately impacted by pollution and climate warming. Funds are also allocated to tackle drought remediation in the West.

I’ve received requests to write on this topic, here are some bits and pieces that I’ve pulled together.  My main points:

  • Post-apocalyptic climate politics have a much better chance of succeeding than fear-driven apocalyptic climate politics
  • Energy policy should be detached from climate policy to make a robust transition to a 21st century energy system that emphasizes abundant, cheap, reliable and secure power with minimal impact on the environment (including land use).

Apocalyptic climate politics

Models, Climate Scientists Wrong Again…New Study Finds Jet Stream Strengthening, Not Weakening

by P. Gosselin,  Aug 9, 2022 in NoTricksZone


Alarmist climate research centers like the Potsdam Institute and the unquestioning media have been claiming for years that the Jet Stream is weakening, hence this would lead to greater weather extremes across the northern hemisphere due to blocking. Responsible for this of course is man-made global warming.

Hat-tip: The Klimaschau

But a recent paper by Samantha Hallam et al published in the journal Climate Dynamics looks at the seasonal to decadal variations in Northern Hemisphere jet stream latitude and speed over land for the period 1871–2011. The authors were unable to find any weakening of the sort climate alarmists have been warning about.

Quite to the contrary, the authors in fact found that the winter jet stream over the North Atlantic and Eurasia has increased in average speed by 8% to 132 mph. The authors found the 141-year trends in jet latitude and speed show differences on a regional basis and that jet speed shows significant increases evident in winter (up to 4.7 ms −1 ), spring and autumn over the North Atlantic, Eurasia and North America. Over the North Pacific, no increase was observed.

Moreover, the Jet Stream was found to have shifted northward by some 330 kilometers. Overall, the paper’s findings contradict the claims of a weakening Jet Stream regularly made by the climate alarmists and their media minions.

Applying climate alarmist science, we’d have to conclude now, due to the strengthening Jet Stream, less weather extremes should be expected. This would be good news of course. But don’t expect the fear-porn media to look at this.

“New Little Ice Age Instead of Global Warming?” — Dr Theodor Landscheidt

by Cap Allon, Aug 7, 2022 in Elecroverse

[Originally published Sept 7, 2020 on electroverse.net]

Among the long list or scientific papers suggesting that a solar-driven spell of global cooling is on the cards, Dr Theodor Landscheidt’s ‘New Little ICE Age Instead of Global Warming?‘ probably has the claim of priority.

Published in 2003, just a year before his death, Landscheidt’s research is standing the test of time, and is still largely on course to be proved correct.

The paper’s abstract begins:

‘Analysis of the sun’s varying activity in the last two millennia indicates that contrary to the IPCC’s speculation about man-made global warming as high as 5.8C within the next hundred years, a long period of cool climate with its coldest phase around 2030 is to be expected.’

Crucially, in the growing list of research concluding that a solar-driven multidecadal spell of global cooling is on the cards (research from multiple studies of quite different characteristics), the year 2030 ALWAYS features prominently. Unlike the IPCC, which tosses its thermageddon doomsday date back and forth like a hot potato, researchers who track the multimillennial plays of the cosmos (namely those of the Sun) routinely land on the year 2030 as being the date of ‘climate deterioration’: this in itself should serve as compelling evidence.

Dr Landscheidt continues:

‘It is shown that minima in the 80 to 90-year Gleissberg cycle of solar activity, coinciding with periods of cool climate on Earth, are consistently linked to an 83-year cycle in the change of the rotary force driving the sun’s oscillatory motion … As the future course of this cycle and its amplitudes can be computed, it can be seen that the Gleissberg minimum around 2030 and another one around 2200 will be of the Maunder minimum type accompanied by severe cooling on Earth. This forecast should prove skillful as other long-range forecasts of climate phenomena, based on cycles in the sun’s orbital motion, have turned out correct as for instance the prediction of the last three El Niño years before the respective event.’

Pacific Typhoons Defy Climate Experts’ Dire Forecasts…Trending Downward 70 Years!

by P. Gosselin, Aug 6, 2022 in NoTricksZone


Pacific typhoons have been trending downward for 70 years 

The Japan Meteorological Agency (JMA) presents the latest data for Pacific typhoons — going back to 1951.

This summer climate alarmists in Europe have been chasing “heat waves”, likely because hurricanes and typhoons have been on the quiet side.

Today we look at the data from the Japan Meteorological Agency (JMA) for the number of typhoons formed in the Pacific in the month of July, now that the July data are available:

 

 

Clearly the world has warmed somewhat since 1951, but contrary to what the climate bedwetters claim, the trend in typhoons has been downward – suggesting that a warmer climate leads to less Pacific storms in terms of typhoons formed. This is the opposite of what climate “experts” said would happen.

Next we look at the number of typhoons formed in the Pacific from January to July, going back to 1951:

 

Tokyo Midsummer Hasn’t Warmed In Decades. And: The Missing Hurricanes”.

by Kyrie, Aug 3, 2022 in NoTricksZone


Continuously increasing CO2 emissions into the atmosphere from the burning of fossil fuels is supposed to be causing warming all over the globe right now, so we should be seeing it in most of the trends.

But often we don’t. The globe, in fact, has cooled somewhat since the El Nino of 2015/16. The media refuse to report that.

One example of no warming is the midsummer mean for Tokyo and its rural Hachijojima island in the Pacific.

Tokyo

Looking at the July mean temperature trend for Tokyo itself, using data from the Japan Meteorological Agency (JMA), and not the adjusted datasets from NASA, we have the following:

The Sahara Is Green When Warm, Desert When Cold…And It’s Drier Now Than The Last Glacial Maximum

by K. Richard, Aug 1, 2022 in NoTricksZone


If wetter is warmer and drier is colder, the modern Saharan climate suggests we are not in a warm period.

It is common knowledge that warmer temperatures are associated with wetter, greener climates, and cooler temperatures are linked to droughts, browning, crop failures, etc.

For example, in the continental US there is a “robust association between pan-CONUS drought events and cold tropical Pacific conditions” (Baek et al., 2019). Again, cooling sea surface temperatures are the “principal driver” of drought across the US.

Why the Sun, Not CO2, Heats the Oceans Revisiting the Debate: Does Greenhouse Back-radiation Warm the Oceans?

by J. Steele, Aug 1, 2022 in WUWT


About a decade ago there was a heated and unresolved debate on whether infrared back radiation from greenhouse gases is heating the oceans. Because infrared penetrates less than a millimeter into the ocean’s surface, many skeptics argued it is impossible to blame rising CO2 for ocean warming. However, several prominent skeptic scientists, people who I have great respect for, also weighed in arguing it was silly and useless to argue infrared heat can’t warm the ocean.

After analyzing the physics detailed in this video, I’m convinced it is solar energy that drives the observed ocean heating, and any infrared ocean heating is insignificant at best. If this analysis holds, it is another significant strike against the prevailing CO2 driven global warming theory

To ensure lay people are brought up to speed, here’s a quick summary of where consensus climate science stands today.

STUDY: 96% OF U.S. CLIMATE DATA IS CORRUPTED

by Heartland Institute, July 27, 2022


Official NOAA temperature stations produce corrupted data due to purposeful placement in man-made hot spots

Nationwide study follows up widespread corruption and heat biases found at NOAA stations in 2009, and the heat-bias distortion problem is even worse now

ARLINGTON HEIGHTS, IL (July 27, 2022) – A new study, Corrupted Climate Stations: The Official U.S. Surface Temperature Record Remains Fatally Flawed, finds approximately 96 percent of U.S. temperature stations used to measure climate change fail to meet what the National Oceanic and Atmospheric Administration (NOAA) considers to be “acceptable” and  uncorrupted placement by its own published standards.

The report, published by The Heartland Institute, was compiled via satellite and in-person survey visits to NOAA weather stations that contribute to the “official” land temperature data in the United States. The research shows that 96% of these stations are corrupted by localized effects of urbanization – producing heat-bias because of their close proximity to asphalt, machinery, and other heat-producing, heat-trapping, or heat-accentuating objects. Placing temperature stations in such locations violates NOAA’s own published standards (see section 3.1 at this link), and strongly undermines the legitimacy and the magnitude of the official consensus on long-term climate warming trends in the United States.

“With a 96 percent warm-bias in U.S. temperature measurements, it is impossible to use any statistical methods to derive an accurate climate trend for the U.S.” said Heartland Institute Senior Fellow Anthony Watts, the director of the study. “Data from the stations that have not been corrupted by faulty placement show a rate of warming in the United States reduced by almost half compared to all stations.”

NOAA’s “Requirements and Standards for [National Weather Service] Climate Observations” instructs that temperature data instruments must be “over level terrain (earth or sod) typical of the area around the station and at least 100 feet from any extensive concrete or paved surface.” And that “all attempts will be made to avoid areas where rough terrain or air drainage are proven to result in non-representative temperature data.” This new report shows that instruction is regularly violated.

READ THE REPORT (PDF).

 

No, Met Office–A Dry July Does Not Mean Climate Change.

by P. Homewood, July 30, 2022 in NotaLotofPeopleKnowThat


So far July 2022 has been the driest July in England since 1911. Up to 26 July there has been only 15.8mm of rain averaged across England; this is only 24% of the amount we would expect in an average July.

At this stage in the month we would expect to have seen well over three-quarters of the month’s rain to have already fallen in an average July.

The situation for the UK is a little better. As it stands, July 2022 is still the eighth driest July since 1836. With only 37.7mm of rain having fallen so far it is the driest July since 1984. Scotland has been closer to average in the north and west, but drier conditions have prevailed for south and east Scotland. Overall Scotland (71%), Wales (39%) and Northern Ireland (43%) have been dry, but the most extreme conditions are in East Anglia and southeast England.

Mark McCarthy, Head of the Met Office National Climate Information Centre, said: “It is not just July that has been dry. Since the start of the year, all months apart from February have been drier than average in the UK too. The result of this is that the winter, spring and summer of 2022 have all seen less than the UK average seasonal rainfall. 

“England has seen the lowest levels during these periods and, rainfall totals for the first six months of the year are around 25% below their long-term average, with the driest regions in the east and southeast.

Germany’s Alfred Wegener Institute Sees No Extreme Situation With Arctic Sea Ice

by P. Gosselin, July 22, 2022 in NoTricksZone


The Alfred Wegner Institute does not see an extreme situation with sea ice in the Arctic (June 2022). The institute’s page states:

The Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI) is participating again this year with the AWI Consortium Model, a dynamic coupled sea ice ocean model, and calculated a September sea ice extent of 4.75 million square kilometers in its June forecast. This value is about 4% above the median value of all submitted models but in the middle of the predictions given for dynamic models.

Dr. Frank Kauker, a physicist in the Sea Ice Physics Section at AWI, assesses the first prediction as follows: “The first forecast of a year from the beginning of June is usually still characterized by a rather large uncertainty (this year 0.43 million square kilometers). Nevertheless, at the moment there is nothing to indicate an extreme situation in September.

The ice cover in September will be with a great probability in the range of the last years, i.e. between 4 and 5 million square kilometers. The next forecast in early July will reduce the uncertainty somewhat, as it will become clear in June how many melt ponds will have formed, which will then decisively determine the melt rates of the ice during the rest of the year due to their lower solar irradiance return.”

New Study: 96% Of U.S. Climate Data Is Corrupted

by Heartland Institute, July 28, 2022  in ClimaterChangeDispatch


A new study, Corrupted Climate Stations: The Official U.S. Surface Temperature Record Remains Fatally Flawed, finds approximately 96 percent of U.S. temperature stations used to measure climate change fail to meet what the National Oceanic and Atmospheric Administration (NOAA) considers to be “acceptable” and uncorrupted placement by its own published standards. [bold, links added]

The report, published by The Heartland Institute, was compiled via satellite and in-person survey visits to NOAA weather stations that contribute to the “official” land temperature data in the United States.

The research shows that 96% of these stations are corrupted by localized effects of urbanization – producing heat bias because of their close proximity to asphalt, machinery, and other heat-producing, heat-trapping, or heat-accentuating objects.

Placing temperature stations in such locations violates NOAA’s own published standards (see section 3.1 at this link) and strongly undermines the legitimacy and the magnitude of the official consensus on long-term climate warming trends in the United States.

“With a 96 percent warm bias in U.S. temperature measurements, it is impossible to use any statistical methods to derive an accurate climate trend for the U.S.,” said Heartland Institute Senior Fellow Anthony Watts, the director of the study.

How Eco-Activists And Lawsuits Are Worsening Wildfires

by J. Wood, July 27, 2022 in Climate ChangeDispatch


With more than three million acres already burned or burning, 2022 is shaping up to be another devastating year for wildfires in the U.S.

America’s forests need to be managed more actively, a task the Biden administration took up earlier this year when it announced a 10-year strategy to reduce excess fire fuels, like downed trees and underbrush, on up to 20 million acres of national forest and 30 million acres of other lands. [bold, links added]

This plan is a step in the right direction, but it’s unlikely to come to fruition if the administration doesn’t first tackle two major obstacles to forest restoration: environmental red tape and litigation.

Projects to clear out fire fuel often face substantial delays. New research from the think tank where I work, the Property and Environment Research Center, found that it takes an average of 3.6 years for efforts to clear downed, unhealthy, and too densely grown trees to move from the required environmental review to on-the-ground work.

For prescribed burns, the delay is even longer, 4.7 years. And these are the averages. Many urgently needed projects take much longer.

While many bureaucratic, technical, and fiscal obstacles affect these delays, red tape and lawsuits are substantial contributors.

Little evidence of changes in extreme weather trends

by P. Homewood, July 27, 2022 in NotaLotofPeopleKnowThat


New IPCC attribution statistics are distorting observational evidence

London, 27 July – A new paper from the Global Warming Policy Foundation finds that the IPCC’s recent shift in methodology has led to misleading claims about changes in weather extremes.

The review, from physicist Dr Ralph Alexander, finds that IPCC claims that many of these weather extremes are increasing significantly are largely unsupported by observational evidence.

Ralph Alexander: Extreme Weather: The IPCC’s Changing Tune (pdf)

According to Dr Alexander:
“On almost every kind of extreme weather, with the possible exemption of heatwaves, the evidence for significant changes is scant. But the latest IPCC report has introduced novel ‘attribution’ statistics and now insists that things are getting worse. It’s yet another case of scientists trying to scare the public into compliance.”

Dr Alexander’s paper looks at:
– droughts
– floods
– hurricanes
– tornadoes
– wildfires
– hot and cold extremes
– coral bleaching.

He concludes that:
“The mistaken belief that weather extremes are worsening because of climate change is more a perception, fostered by media coverage, than reality. The IPCC’s new statistical method is playing an unworthy part in bringing this sorry state of affairs to pass.”

GWPF invited the Royal Society and the Met Office to review this paper, and to submit a response to be published as an appendix to it. No reply was received.

The IPCC And The Infamous Hockey Stick Graph

by CCD Editor, July 25,2022 in ClimateChangeDispatch


Ron Barmby, author of  “Sunlight on Climate Change: A Heretic’s Guide to Global Climate Hysteria” (AmazonBarnes & Noble) spoke with Mike Ryan of TNT Radio (TNT Radio (podbean.com) about what he uncovered in the recent IPCC report, Climate Change 2021: The Physical Sciences Basis.

Ron’s findings: after being made famous by Al Gore and adopted by the IPCC, then being made infamous by its historical and statistical failings and subsequently dropped by the IPCC, the hockey stick temperature graph is back!

And a new narrative is being introduced that carbon dioxide has been demoted to causing only half of human global warming to date.

Mike discusses with Ron the four things wrong, and often in conflict with, the report itself with the latest doomsday science from the IPCC. LISTEN:

LARGEST SUMMER SEA ICE EXTENT SINCE 2008 TRAPS ARCTIC SHIPS; + COLDEST JULY AIRMASS IN 70 YEARS BLOWS THROUGH THE BERING STRAIT

by Cap Allon, July 19, 2022 in Electroverse


The mainstream are heat-chasers. They report only on stories that fit the AGW Party agenda. This cherry-picking leads to a painfully misinformed public when it comes to the climate–which is exactly where they want us.

It usually stands, however, that if the MSM goes silent on a particular locale then it’s probably because that particular locale isn’t ‘behaving’ as they would like.

ase in point today: we have the Arctic and Greenland refusing to play ball.

Earth’s most-northern reaches are actually experiencing persistent and long-lasting COOLING, which is far more telling than a brief burst of heat in, for example, Western Europe, which, 1) is forecast to be over before it’s even really begun, and 2) can be tied to entirely natural forcings–namely low solar activity and a violently ‘buckling’ jet stream flow (more on that below).

UK heatwave: How do temperatures compare with 1976?

by P. Homewood, July 24, 2022 in NotaLotofPeopleKnowThat


People on social media have been comparing the high temperatures in much of the UK with the heatwave of 1976, suggesting that the severity of the current hot weather is being exaggerated.

So, what does the evidence show?

How hot was the summer of 1976?

The peak that year was 35.9C. That has been beaten by the current temperatures, with 40.3C recorded so far.

The heatwave of 1976 started in June and lasted for two months. There was a lack of rainfall and a significant drought, with the government enforcing water rationing.

The heatwave was rare for that decade. The average maximum temperature in July in the 1970s was 18.7C. In the 2010s, it was more than 20C.

The European Heat Wave and Global Warming

by Guest Blogger, July 21, 2022 in WUWT


From the Cliff Mass Weather Blog

There is a lot of talk about the short-term European heatwave with some suggesting that the record-breaking warmth is the result of climate change/global warming.

Some of the media and climate advocates have been over the top in their claims (see below), stating that this event was the result of human-caused global warming.

Global Warming Has Stalled Over Much Of The Last 10 Years, Arctic Never Melted Away

by P. Gosselin, July, 22, 2022 in NoTrickZone


The globe hasn’t been warming and the Arctic hasn’t been melting much for almost a decade now.

Recall the climate crisis loonies warned us some 20 years ago the Arctic sea ice would disappear by the summer of 2014. Well it’s still very much there, as Joe Bastardi reminds us at his most recent Saturday Summary:

No warming in 8 years

Moreover, UAH global mean temperature anomaly hasn’t risen in eight years as well, Hat-tip Snowfan here:

….

Was It Hotter In 1911?

by P. Homewood, July 23, 2022 in NotaLotofPeopleKnowThat


There has inevitably been a lot of apoplectic reporting about this week’s heatwave in Britain. Everybody from the BBC to the Met Office have been blaming it on climate change, with suitably scary colours to ram the message home:

Comparison of TV weather Maps from the BBC in summer 2012, left, and summer 2022 right. Source: BBC

Courtesy of Climate Realism

But so far I have not seen an objective analysis.

So let’s start with a few simple facts:

1) It was extremely hot for a couple of days this week.

2) The heat was the result of an extremely unlikely set of meteorological conditions – a perfect storm, if you like.

We know this because the Met Office told us so. On July 8th, they announced the possibility of a heatwave a week later. The weather model runs produced a wide band of possibilities, with most predicting similar temperatures to the weekend before, and some even forecasting no heatwave at all. At that stage on a couple of models out of the hundreds run predicted 40C temperatures, which were described by the BBC as “a very tiny possibility”.

 

Climate Monitoring Since The Little Ice Age

by P. Homewood, July 19, 2022 in NotaLotofPeopleKnowThat


Meanwhile the jokers at the Met Office don’t seem to have realised that their temperature records begin at the depth of the Little Ice Age, or appear to have heard about Urban Heat Islands

It is mid July 2022. We are currently experiencing a significant – at the time of writing provisionally record-breaking – heatwave for the UK. Red weather warnings for extreme heat are in force for large parts of England and forecasts indicated a real possibility of temperatures reaching up to 40°C in some areas. Indeed, this temperature has already been exceeded. Whether or not records are broken, a key part of the work that we do at the Met Office is climate monitoring, an important aspect of which is the ability to put current weather into historical context. Climate monitoring serves many functions: It can effectively communicate the relative severity of an event; it can indicate how frequently such extremes are likely to occur; and it can monitor how the character or frequency of extremes are changing over time. In order to properly understand the risks from climate change, a key research question climate monitoring can help us to answer is, ‘What are the current weather and climate hazards, risks and impacts that should be expected in the UK and globally?’. To address this question, we must look to the past, and the scientific effort goes back further than you might think.

Making history

In 1663, Robert Hooke stood before the relatively newly formed Royal Society and proposed ‘A method for making the history of the weather’. Hooke and other notable scientists of the time were actively developing instruments capable of making meteorological measurements of wind, rain, air pressure, humidity and temperature. These were the early anemometers, rain gauges, barometers and thermometers of the time1. In his paper, Hooke recommended what should be measured and how it should be recorded, including ‘a scheme at one view representing to the eye the observations of the weather for a month’ and implored his colleagues to undertake such measurements. From a modern climatologist’s point of view, arguably one of the most important advances by Hooke was his recognition that if systematic and consistent measurements were made across the country, or even across the world, then an international perspective on the weather could be obtained, for the benefit of humankind. 

The Two Degree Limit

by Andy May, July 19, 2022 in WUWT


For decades We have been told that we must not let global warming exceed two degrees Celsius above the “pre-industrial” global average temperature. Recently the IPCC lowered this limit to 1.5°C. In the latest IPCC report, called AR6, pre-industrial is defined as before 1750, but they use global temperatures from 1850-1900 as representative of the period because global average surface temperatures are not available for 1750.[1] The U.S., Europe, and much of Asia were industrialized by 1900, so their numbers are clearly not representative of the period of interest, unless temperatures remained constant from 1750 to 1900, which is unlikely.

Why the focus on 2°? In a 2014 comment in Nature, David Victor and Charles Kennel tell us that there is little scientific basis for the 2°C figure, but it was a simple focal point and it “sounded bold and perhaps feasible.” (Victor & Kennel, 2014). Then they admit the goal is “effectively unachievable.”

What is the “pre-industrial?” Did it have an ideal climate that we wish to return to? The year 1750 was in the coldest and most miserable part of the Little Ice Age (LIA). The LIA was the coldest period in the Holocene Epoch, or since the last glacial period ended about 12,000 years ago, at least in much of the Northern Hemisphere.