On this page you will find basic background information on climate, such as the planet’s geological history and the real effects of CO2 on climate (i.e., not nearly as much as we’re told), that every informed citizen should know in assessing alarmist claims of climate doom ahead.
Articles on this page
- Climate at a Glance
- Lessons from climate paleontology
- There is a negative correlation between CO2 and global warming
- A graphic guide to climate realism
- Using Woodfortrees for temperature data
Climate at a Glance
Climate at a Glance gives short, factual summaries of the realist position on 30 climate issues, from rising sea levels to “ocean acidification” to the sensitivity of temperature to rising levels of CO2. It also includes a PDF download of Anthony Watts’s (Watts Up With That website) book version for teachers and students. The site is worth more than a glance!
Lessons from climate paleontology
Below is a link to the YouTube video of a talk by Canadian earth scientist Tom Gallagher, who looks back through 66 million years of the earth’s history and reviews the factors that have affected the climate. He points out how commonly used climate “models” ignore this historical data and end up focusing on the wrong factors. It’s an “Everything you ever wanted to know about paleoclimate but were afraid to ask”! To see this video, click here.
There is a negative correlation between CO2 and global warming: or How to save more than $1 trillion a year!
By Patrick Hunt, Feb. 13, 2022
I am an environmentalist. My economics honours paper five decades ago was entitled “Pollution in Perspective” and it proposed ways to finance the cleanup of our land, water and air.
There has been a lot of media coverage over the recent years about “greenhouse gases” (GHG), and that the cause of global warming is increasing amounts of carbon dioxide (CO2), especially man-made or anthropogenic CO2, in the atmosphere. I have many environmentalist friends who have that belief and are convinced that human-made CO2 is the thermostat that is causing global warming.
I began to look at climate change more closely in June 2004 when I observed two unrelated graphs in separate rooms at the Royal Tyrrell Museum of Palaeontology in Drumheller, Alberta. One plotted atmospheric CO2 over 4.6 billion years of the Earth’s existence and the other plotted the world’s average surface temperature over the same period. I walked back and forth between those two rooms at least 10 times to confirm my observation; there was NO correlation between the two graphs that I could observe! There was no overlapping trendline.
Afterwards, I began to research in earnest the correlation between CO2 and temperature over geological time. What I found is a weak negative correlation of -0.19. In other words, CO2 and temperature are not strongly correlated. (For details on how correlation is assessed, see “Appendix: Coefficient of Correlation Explained” below.)
I then became aware of the elaborate efforts being made to silence anyone who dared question the supposed scientific consensus that anthropogenic CO2 was the primary cause of global warming. I realized that many of the arguments supporting the Intergovernmental Panel on Climate Change (IPCC) narrative were questionable because they were based on computer models that did not correspond to direct observation. Some even relied on altering historical records to support the IPCC hypothesis, including the Michael Mann “hockey stick,” which eliminated the Medieval Warming Period (roughly 950-1250 AD) to hide the fact that CO2 has gone up since then, while temperatures has gone down (negative correlation).
I am not a climate change denier, and I know no one who believes the climate has not changed. But there are plenty of well-informed people, including reputable scientists, who question the IPCC hypothesis. There is ample evidence that the climate has always been changing, with cycles of warming and cooling, and continues to change today.
What creates the Greenhouse Gas effect?
Water vapour makes up 95% of the Greenhouse Gas (GHG) effect. CO2 is also a greenhouse gas, but its impact on the earth temperature is small and its added impact diminishes with its concentration in the atmosphere. CO2 represents only 3.6% of the total GHG effect. Human activities are only responsible for 3.2% of the total production of CO2; this means that human-generated CO2 is only 0.12% of the total GHG effect.
Naturally occurring CO2 makes up the other 96.8% of the CO2 production, consisting of such things as rotting vegetation, animals exhaling, and volcanic eruptions. Even if every human on earth were to die tomorrow, the impact on the GHG effect would be insignificant—less than a rounding error.
If there had been a Conference of the Parties, similar to the 2015 Paris conference, in Glasgow in 1970, the climate crisis that world leaders and environmental scientists would have been discussing would have been global cooling.
In fact, sixty years ago many scientists were predicting the start of a new Ice Age. The temperature was higher in the 1930s during the “dustbowl” period than the temperature is today. During the 1940s, 1950s and 1960s, the global temperature was decreasing, and some scientists then were speculating that the increase in CO2 was causing global cooling. The earth’s temperature started to rise again in the early 1970s but peaked in 1998 and has more or less levelled off since. All during this time, the atmospheric CO2 level kept rising.
In 181 BC Hannibal drove his elephants through the Alps to battle the Romans. This could not be done today because the mountain passes are now filled with snow year-round. In other words, it was warmer 2,203 years ago, when CO2 was only 260 ppm compared to today’s 417 ppm. There has been a 60% increase in CO2 since 181 BC but, oddly, the temperature has gone down, not up!
No one would deny that CO2 is an essential plant nutrient. As CO2 has increased in the atmosphere, so too has the global biomass, the total amount of plant and animal life on Earth (and particularly plant life). Why? Because plants grow bigger and faster with more CO2 and they require less water. Over the 50 years that satellites have been able to make accurate measurements, Earth’s biomass has increased by 20 percent. Seventy percent of that increase has been attributed to the increase in CO2.
Astrophysicists tasked with finding planets in other solar systems that might be conducive to life do not look for planets with a similar temperature to the Earth’s; they look for planets that are 5°C warmer than the earth’s present temperature. (See “In Search for a Planet Better than Earth: Top Contenders for a Superhabitable World” by Dirk Schulze-Makuch, René Heller, and Edward Guinan, 2020.) As one astrophysicist put it, “There is more biomass and diversity of species at the equator than at the poles!”
What else could cause climate change if it is not CO2?
Numerous scientists have identified the Sun as the main cause of climate change! For instance, the Milankovitch Cycles explain changes in the Earth’s climate and surface temperature as a result of changes in the Earth’s orbit, as the Earth’s orbit cyclically changes the distance from the Sun and its axial tilt toward or away from the Sun. Milutin Milankovitch, a Serbian geologist and astronomer, also observed a strong correlation between the number of sunspots and the temperature on earth (more sunspots = more warming and vice-versa).
Other factors that affect the Earth’s climate and surface temperature are:
- variations in the Sun’s luminosity
- variations in the Sun’s magnetic field
- cosmic rays
- the Earth’s magnetic field
- the amount of heat stored in or released from the oceans
- the Earth’s atmosphere itself.
The Sun causes climate change not only on Earth, but on other planets and moons in our solar system (see H.I. Abdussamatov, “The new Little Ice Age has started,” Elsevier, 2016.)
Original research by Tom Gallagher, a Canadian geoscientist, has found strong correlations between major temperature changes and continental drift, which has opened and shut gates at the Bering Strait and Panama Isthmus, as well as the flow through the Mediterranean and the Arabian Gulf north of India, before India became attached to Asia. Gallagher also points to the role of the oceans as a store of 83% of the Earth’s CO2 and a store and transporter of energy over time and around the world.
From his research Gallagher concluded that “CO2 and temperature proxies do not correlate in geologic climate data” and that over geological time there is a very weak, negative correlation between CO2 and temperature—a slight inverse correlation. His video is available at: https://youtu.be/K6tWEjkEiZU.
To argue that CO2 is the thermostat regulating the earth’s temperature, one must prove a positive correlation, and preferably a strong correlation, exists between CO2 and temperature.
The relationship Between CO2 and temperature
Atmospheric CO2 is presently at approximately 417 parts per million and the mean Earth temperature is 14.6°C. Scientists have established that CO2 has varied in ppm over the last 550 million years from a low of 180 ppm to a high of 7,000. But what have been the corresponding temperatures over that time? Various studies, using proxies (e.g., tree-ring data from the past), have calculated both CO2 and temperature over various time frames.
The graph below plots CO2 and temperature over the last 550 million years. It is by Dr. Horst-Joachim Lüdecke, who created this graph by overlaying a graph of CO2 going back 550 million years, found in a 2003 Nature magazine article, with another graph of the Earth’s temperature over the same period, found in a 2007 Nature magazine article. The title of his paper is “Data From 2 Independent Studies Show No Correlation Between CO2 And Temperature”, July 30, 2020. (See: www.climatedepot.com/2020/07/30/data-from-2-independent-studies-show-no-correlation-between-co2-and-temperature.)
The first red arrow points out a time when CO2 was high while temperature was low. The second red arrow points out a time when CO2 was low while temperature was high.
If increases in atmospheric CO2, and specifically anthropogenic CO2, were the cause of global warming, as claimed by the Intergovernmental Panel on Climate Change (IPCC), then the Earth could not have been in an Ice Age when CO2 was over 4,000 ppm, as it was 440 million years ago.
What Prof. Lüdecke clearly shows in the above graph confirms what I first observed at the Royal Tyrrell Museum. As Prof. Lüdecke concluded, “The result shows the long-claimed atmospheric CO2-global temperature correlation doesn’t exist.” In other words, without correlation, there can be no causation. The lack of correlation disproves the hypothesis that man-made CO2 is the primary cause of global warming, the IPCC’s main hypothesis.
Before committing billions of dollars in an attempt to reduce CO2, the Canadian government (and all other governments) should do a proper cost-benefit analysis of its goal of Net Zero by the year 2050. It should also do a proper cost-benefit analysis of the effects of doubling CO2 and increasing the temperature 2°C by 2100. Bjorn Lomborg does this cost-benefit analysis in his 2021 book, False Alarm: How Climate Change Panic Costs Us Trillions, Hurts the Poor, and Fails to Fix the Planet. It should be required reading for anyone interested in the massive cost of try (and failing) to stop climate change.
If CO2 is not the primary cause of global warming, why should we approve of the world governments, including our federal, provincial, and municipal governments, collectively spending trillions of dollars each year in a futile attempt to control global warming by cutting CO2 to meet their Paris Accord agreements?
The McKinsey Global Institute report entitled “The net-zero transition: What it would cost, what it could bring” (January 25, 2022) estimates the cost to the world economy of reaching the goal of Net-Zero by 2050 would be US$275 trillion, or US$9.2 trillion per year.
Canada produces about 2% of the world output of anthropogenic CO2, so its 2% contribution to the global cost would be US$5.5 trillion, or US$183 billion per year. This works out to CDN$186,480 for each Canadian, or CDN$6,216 per year per person in today’s dollars! For a family of four that’s CDN$24,864 a year that could be spent on other, more necessary things. Yet this considerable amount of money that will have almost no effect on global temperatures.
So, I ask those who believe in the theory that man-made CO2 is the primary cause of global warming:
- What scientific evidence do you rely on?
- What Coefficient of Correlation between CO2 and temperature do you use? Over what period of time?
- What are the costs, and what are the benefits, of a world that has 800 ppm of CO2 and is 2°C warmer than today? What is wrong with a warmer world with more plant food (CO2 is a fertilizer) anyway?
- Is it not cheaper and more certain to adapt to climate change than to attempt to prevent climate change?
- What if most countries do not honour their CO2 reduction commitments (as the vast majority will not)? What then?
- Are you personally willing to risk CDN$186,480 for every Canadian over the next 30 years to test your hypothesis? I am NOT.
Appendix: Coefficient of correlation explained
The coefficent of correlation, symbolized by “R”, is a statistical measure of the strength of the relationship between two variables. The values range between -1.0 and 1.0.
- An R greater than 1.0 or less than -1.0 means that there was an error in the correlation measurement.
- A correlation of -1.0 shows a perfect negative correlation (no correlation at all), while a correlation of 1.0 shows a perfect positive correlation (the two variables are highly correlated).
- A correlation of 0.0 shows no linear relationship between the two variables.
- If R is between -0.5 and 0.0 or between 0.0 and +0.5, it is considered a weak correlation and statistically cannot be relied on.
Below is a scatter plot of CO2 and temperature over time, created by W. Jackson Davis in his paper “The Relationship between Atmospheric Carbon Dioxide Concentration and Global Temperature for the Last 425 Million Years” Graph 6 (Sept. 29, 2017, “Climate 2017.”) The paper can be found at http://www.mdpi.com/2225-1154/5/4/76 and gives the math and methodology used to establish its conclusion.
If CO2 was driving temperature, i.e., there is a strong positive correlation, then the red dots should form a straight line from the bottom left and ascending to the top right (that is, low levels of CO2 and a low temperature moving upward in lock-step as more CO2 created higher temperatures).
The closer the dots are to forming a straight line, the stronger is the correlation. If all the red dots were exactly on the straight line, the coefficient of correlation would be +1, which is as strong a correlation as possible. The blue line represents the calculated coefficient of correlation (R) of CO2 and temperature over the last 425 million years. The coefficient of correlation is -0.19, which is weak. Again, anything between -.05 and +0.5 is considered a weak correlation.
Without strong correlation, you cannot have causation. This lack of correlation between CO2 and temperature over 425 million years proves that recent changes in CO2, whether human-caused or natural, could NOT be the primary cause of recent changes in temperature (i.e., the feared “global warming”).
CO2 is a greenhouse gas and it can influence temperature, but it does not control temperature like a thermostat would. If the world focuses on only one minor factor in climate, CO2, as the IPCC does, and ignores the major factors that do strongly correlate with changes in temperature, we are wasting our talent, time and treasure. This is the climate realist position.
A graphic guide to climate realism
By Ken Wilson, P.Eng (Ret.)
The Intergovernmental Panel on Climate Change (IPCC) makes two key claims:
- Claim 1: CO2 emissions from fossil fuels are the primary driver of climate change.
- Claim 2: Climate change due to CO2 emissions is causing unprecedented changes in the weather.
The graphs below disprove both claims.
Figure 1 summary: There is no consistent correlation of CO2 driving temperature on the geological time scale. Current CO2 and temperature values are near the lowest levels that they have been in the past 550 million years. In the great explosion of visible life forms in the Cambrian Period 540 million years ago, CO2 levels were in the 6,000 ppm range versus today’s 415 ppm range.
Figure 2 summary: Over the last 140 million years, CO2 levels fell precipitously and steadily to within about 30 ppm of the 150 ppm “line of death” below which plants can’t survive. Both the relatively short-term data (hundreds of thousands of years) from ice cores and much longer-term data going back 140 million years (Berner 2001) show an alarming downward trend toward CO2 starvation. The release of carbon dioxide by the use of fossil fuels has allowed humanity to increase concentrations of this beneficial molecule, and perhaps avert an actual CO2-related climate apocalypse.
Figure 3 summary: The Lawrentian ice sheet stretched from Alberta to the Atlantic. Sea level dropped by 120 meters during the last glacial advance due to the storage of water in glaciers and ice sheets. Most of the glaciers and all the remnants of ice sheets melted in about 8,000 years due to natural causes. It was clearly not due to the burning of fossil fuels by humanity.
Figure 4 summary: The Interglacials last about 10 to 25 thousand years, before the onset of the next glacial advance. We are currently at the 12,000-year mark in our current Holocene Interglacial.
The previous Interglacial, the Eemian, 130,000 years ago, was warmer than today’s. Sea level was estimated to be 4 to 6 meters higher than today’s.
Polar Bears survived both the Holocene Maximum which occurred about 7,000 years ago, and the Eemian Maxim 130,000 years ago. The Polar Bear population has been rising for several decades now as a result of the hunting regulations that were introduced by all the circumpolar countries in the 1950’s.
Our current ice age has been underway for about three million years. In that time, we have had about 50 glacial advances and retreats. The earlier cycles lasted about 40,000 years, compared to the current cycles that have lasted about 100,000 years.
When the above pattern is looked at in an expanded time scale, the rise in CO2 is seen to lag the rise in Temperature by about 800 years. This has been consistent during our current ice age until now. The lag time has been due to the slow outgassing of CO2 from the oceans as the oceans slowly warm.
The exception now is shown at the extreme right end of the graph where CO2 (the blue curve) has climbed rapidly due to the burning of fossil fuels, particularly since the end of WW II. So far, this has had no significant effect on Temperature rise (the red curve).
Figure 5 summary: About 12,000 years ago, the earth entered the Holocene Interglacial. The Holocene Maximum temperature occurred about 7,000 to 8,000 years ago. At that time, almost all of the mountain glaciers and all of the remnants of the ice sheets had melted. The summer temperature in Canada during the Holocene Maximum was estimated to be about 4°C higher than today. There was a spruce forest at Tuktoyaktuk, with cattails growing in the forest. It is all tundra today. The northern limit of growth for cattails is several hundred kilometers to the south.
Since the Holocene Maximum, the temperature has been trending down, but with periodic short reversals such as the Roman Warming and the Medieval Warming. At the same time, CO2 was trending up, which is contrary to the IPCC’s assumption that rising CO2 is a primary driver of global warming.
Also, glaciers have begun to reform, with a notable advance of glaciers occurring in the Little Ice Age that ended about 1850. We are currently in the Modern Warm period in which the global temperature has risen about 1.07°C in the past 170 years. This is not an alarming temperature rise. It is similar in character to what occurred in the Medieval and Roman Warmings. At the end of the Little Ice Age, CO2 was at about 280 ppm. It is currently about 415 ppm.
Figure 6 summary: This is the longest measured temperature record in the world. It represents a roughly triangular area between London, Bristol and Preston. Since 1974, temperature has been adjusted to compensate for Urban Heat Island Effects.
The solid black line shows the estimated emissions of CO2 since the beginning of the industrial revolution. The short vertical dotted black line marks the end of WW II, and the beginning of the rapid increase in the use of fossil fuels to support the rise in living standards in both developed and developing countries. The large increase in CO2 emissions has had little much effect on the Central England Temperature record.
The current temperature rise is only unprecedented since the end of the Little Ice Age. It is certainly not unprecedented with respect to the temperature at the Holocene Maximum 7,000 to 8,000 years ago.
Figure 7 summary: A detailed examination by John Christy, a distinguished climatologist at the University of Alabama at Huntsville (UAH) and Alabama State Climatologist, provides a stark assessment of the validity (or non-validity) of the models used to support an imagined apocalypse. His testimony in February 2016 to the U.S. House Committee on Science, Space and Technology included remarkable charts that document just how much the models overestimate temperatures.
The red line in the chart shows the average of 102 climate model runs compiled by Christy and his team at UAH using the models on which the IPCC itself relies. Also shown on the chart are the actual, observed temperatures (three colored lines) from three different sources. The IPCC models exaggerate warming, on average, by two and a half times the actual temperature (or three times over in the climate-crucial tropics).
In other words, the modeling results are not accurate enough to serve as a reliable basis for formulating long-term government policies on global warming.
Melting glaciers and rising sea levels are the direct result of warming. The evidence shows that the global warming causing the rise in sea levels and the retreat of the glaciers began long before any significant man-made CO2 increases could have influenced either. Both are directly the result of the natural warming that began in the late 17th-century.
Glaciers could not begin to retreat and seas to rise until the atmosphere had warmed sufficiently to allow summer ice loss to exceed winter accumulations. That glacial “tipping point” occurred around 1800, with full-on retreat by 1850. Thus began more than 150 years of worldwide glacial retreat and sea-level rise that continues at about the same rate today as 150 years ago.
This is not an alarming rate of seal level rise, nor is there an unusual increase in the rate of rise in recent years. The current rate of rise can be dealt with by regular adaptation measures, such as raising dikes and levees and better floodplain management practices.
Figure 9 summary: The frequency of tropical cyclones overall is diminishing. The number of major hurricanes of Category 2, 3, 4 or 5 strength seems to show a slight increase over this period, but this trend has been ascribed to improvements in observational capabilities rather than warming oceans that provide the fuel for cyclones. The IPCC predicts fewer hurricanes overall in a warming world, but also expects more of these hurricanes to be in the severe Category 4 and 5 type.
Figure 10 summary: Between 1954 and 2017, the globe warmed approximately 0.7°C (1.3°F) and climate alarmists have warned that warmer temperatures will mean more extreme weather in the form of tornadoes. However, tornado activity in the United States can vary drastically from year to year. In 13 successive days of tornado outbreaks in 2019, well over 400 tornadoes touched down in May, with June a close second; this followed seven quiet years ending in 2018, which was the quietest year in the record since 1954.
The tornado surge, however, had nothing to do with climate change, but rather an unusually cold winter and spring in the West that, combined with heat from the southeast and late rains, provided the ingredients for severe thunderstorms. Figure 10b shows the number of strong (EF3 or greater) tornadoes observed in the U.S. each year during 1954-2017. Clearly the trend is downward, not upward: the average number of strong tornadoes annually from 1986 to 2017 was 40% less than from 1954 to 1985. Once more, global warming cannot have played a role.
In the U.S., tornadoes cause about 80 deaths and more than 1,500 injuries a year. The most deadly episode of all time in a single day was the ‘tri-state’ outbreak in 1925, which killed 747 people and resulted in the most damage from any tornado outbreak in U.S. history. The most ferocious tornado outbreak ever recorded, spawning a total of 30 EF4 or EF5 tornadoes, was in 1974. These occurred well before “human-caused global warming” can be blamed.
Figure 11 summary: Because modern global warming was barely underway in the 1930s, climate change clearly has nothing to do with the burning of U.S. forests. The same trend appears in data on the estimated area worldwide burned by wildfires, by decade from 1900 to 2010. Clearly, wildfires have diminished globally as the planet has warmed. (Alexander RB (2020) Weather Extremes: Are they caused by global warming? Report 43, GWPF)
Why is the damage from forest fires falling? Suppression of forest fires and conversion of forest land to farmland has decreased the area damaged by forest fires. The conversion of forest land to subdivisions, such as semi-arid areas like California and South Australia, has resulted in more deadly and damaging fires when they do occur due to the accumulation of forest litter in close proximity to houses.
Figure 12 summary: The world’s remarkable ability to increase food production year after year is attributable to mechanization, agricultural innovation, CO2 fertilization and warmer weather. World grain production and amount harvested per acre show that crop and food production has steadily increased, with only positive effects from our changing climate. If more CO2 and warmer weather were going to cause a decline in worldwide food production, should there not have been some recognizable negative effects by now? Contrary to predictions, all the signs point to robust food production, which will increase far into the foreseeable future. For this, we can be grateful for a combination of rising temperatures and increasing carbon dioxide.
Source(s): CO2: Boden TA, Marland G, Andres RJ (2016) Global CO2 emissions from Fossil-Fuel Burning Cement Manufacture and Gas Flaring 1751-2013. CDIAC, Temp: HadCRUT4 (2017) The Hadley Climate Research Unit (HadCRUT4) annual global mean surface temperature dataset
The facts about CO2
CO2 is an essential compound for the existence of almost all life on the planet. When CO2 had reached a level of only 180 ppm about 20,000 years ago, the planet was dangerously close to the shutting down of most plant and animal life (this would occur at 150 ppm). The recent rise in CO2 levels to about 415 ppm is producing more resilient plants, faster growth, and more drought-tolerant plants, which is contributing to record levels of food production and to a significant greening of the planet.
Despite this well documented benefit from higher CO2 levels, the U.S. Environmental Protection Agency (EPA) has declared CO2 to be a pollutant. The EPA and many U.S. legislators are trying to regulate CO2 producers out of existence as quickly as they can.
This illustrates the extraordinary lack of scientific knowledge at senior government levels that permeates most western societies at this time. It also illustrates the adverse consequences created by the irrational level of fear in most western nations over the alarmists’ claims that the world is facing an imminent global-warming apocalypse due to rising CO2 levels. There is no observable evidence in the past 550 million years of record to justify such a fear.
The real problem the planet is facing is not from rising CO2 emissions from fossil fuels but the flawed IPCC computer modeling results based on faulty assumptions, assumptions that have led alarmists to demand that the world replace existing efficient high density fossil fuels with unreliable, intermittent, and very costly green energy. The current energy chaos in the UK and EU in trying to convert to green energy and phase out fossil fuels highlights the major social and economic consequences that result from adopting low-density green-energy alternatives.
Fig12 shows a period between the early 1970’s and the late 1990’s, when the IPCC models were being developed, when there was a brief period of apparent correlation between rising CO2 and rising temperatures. But this apparent correlation breaks down if you look back in geological time (see Figures 1 and 2), which clearly shows that natural forces, which have mostly been ignored by the IPCC in its models, are controlling what is actually happening in the atmosphere. We have still to learn what these natural forces are.
Final Note: I added summary notes based on many sources of observed data that are readily available in climate-change literature. The graphs’ overall message is that the current hysteria over global warming not warranted because key claims based on the IPCC’s computer modeling are not supported by observed data.
Using Woodfortrees.org to get temperature data
By Paul MacRae
Wouldn’t it be nice not to depend on often-biased or inaccurate media reporting to get information on what the global temperature is actually doing? Fortunately, there is a way to get this information at the website Woodfortrees.org.
Woodfortrees.org offers a gadget that allows anyone to access the temperature anomalies (the ups and downs of temperature) going back to the mid-1800s. Note that this is not the actual temperature; it is the temperature compared to a previous, baseline 30-year period, such as 1961-1990 or 1981-2010 (hence “anomaly” or variation from the norm). That said, the temperature anomaly does give you a good idea of how and whether the temperature is changing (or not).
On the website’s main page, click “Interactive” in the upper menu and you will get Figure 1:
Clicking on “Temperature (monthly anomalies)” will give you a list of the five major climate monitoring centres and their variations: Britain’s Hadley Institute (HadCrut) and NASA’s Goddard Institute for Space Studies (GISS, shown as GISTEMP), both of which use temperature monitors on land and sea; and the two satellite-based monitoring services, Remote Sensing Systems (RSS) and University of Alabama at Huntsville (UAH) (see Figure 2).
Satellite-generated temperatures are generally considered more reliable than land-and-sea generated temperatures because satellites are less affected by local conditions (e.g., a land-based monitor near a concrete wall will show temperatures warmer than they actually are). However, satellite temperatures only go back to 1978.
Finally, there is Berkeley Earth Surface Temperatures (BEST), which I’ve ignored because it doesn’t add much.
Woodfortrees collects the temperature data from these five centres. It also offers an average of the five centres’ data as its “WoodForTrees Temperature Index.”
To get the temperature anomalies for any range of years, from present day to as far back as the mid-1800s, for land-and-sea data, or from 1978 for satellite data, you fill out the green box to the right of the graph box.
Click on a “Data source” (in the example in Figure 3, the “UAH6.0 lower trop. global mean”). Under “Processing steps”, click #1 “From (time)” and put in a date (in the example, “2000”). #2 is “To (time)”, and I’ve put “2021”. Click on “Plot graph.” A white box with the temperature changes as a colored line will appear to the left of the green box.
Now what’s needed is a trend line so you can see whether temperatures have increased, decreased, or stayed the same. To get a trend, click on “Add series.” Another green box labelled “Series 2” will appear. Enter the same temperature source (e.g., “UAH6”) and beginning (#1) and end (#2) dates, but in box #3, a click will get you a different list of options. Choose “Linear trend (OLS)” (Figure 4).
Click on “Plot graph” and you’ll get the following result, showing both the temperature anomalies in red and a trend line in green. As you can see in Figure 5, the trend line is a bit “up” for 2000-2021.
For comparison purposes, you can display the temperatures of two or more of the monitoring agencies’ on one graph. To do that click “Add series” on the lower left of the green boxes, then choose your “data source” and the “from” and “to” times. This time we’ll select “HadCrut 4 global mean” as the source and the same years (2000-2021). For a trend line, click on “Add series” and repeat the “data source,” “from” and “to” information, then again pick “Linear trend” in #3. Continue for as many centres as you want (yes, it is tedious). The result for two agencies looks like this:
When you hit “Plot graph” in the lower left of the green boxes you will get the graph to the right, Figure 7, which compares the two temperature sets, with each set and trend line shown in a different colour (blue and purple for HadCrut, red and green for UAH).
Why are the results different in terms of vertical temperature (blue line above the red line)? This is an anomaly graph, based on a previous 30-year period. Hadley’s (blue) temperature is higher on the vertical because it is based on the 1961-1990 period, which was colder than, say, 1981-2010, the base period for UAH. (In the 1970s many scientists thought the planet was heading for another ice age; thus, the comparison anomaly baseline for HadCrut is lower and its temperature line will appear higher.) Otherwise, the two lines are more-or-less in parallel.
Figure 8 shows the results for four of the agencies from 2000-2021: HadCrut, GISS, RSS and UAH. Again, they pretty much agree on the ups and downs of temperature, while differing slightly on the vertical, temperature scale. You can also see an upward trend line of roughly .4°C, or about .2°C per decade. Over a century that would be a temperature increase of 2°C, which is far from the “catastrophe” zone.
When I was writing False Alarm: Global Warming Facts Versus Fears from 2007-2010, the temperature from 2000 to 2010 was pretty much flat, as shown in Figure 9 for the four agencies. UAH’s satellite readings even showed a decline in temperature! Yet during this decade, the IPCC 2007 report described the evidence for global warming as “unequivocal” and, in 2008, IPCC chair Rajendra Pachauri told an Australian audience that warming was “accelerating.” So during ten years when the “global-warming” frenzy was at its height (Al Gore’s Inconvenient Truth film came out in 2006), with many claims of doomsday looming, there was virtually no warming.
It was thus fairly obvious to me that the fix was in and these apocalyptic claims were not objective science based in facts but “science” based in global-warming ideology. That said, as noted in Figures 7 and 8, temperatures have increased a bit in the past two decades overall, but certainly not enough to justify claims of a climate “emergency.”
With the climate monitoring agencies’ actual data, Woodfortree allows us to fact-check the global warming alarmists’ highly exaggerated claims of apocalypse.
One other thing: The anomaly graphs present a picture of considerable ups and downs in temperature, particularly during very warm El Nino years (the spikes upward). This is because the temperature range on the left vertical axis is about 1° Celsius. In other words, all these changes are occurring within a relative narrow range of temperature. In most cases, you wouldn’t even notice the differences.
If we zoom out from this narrow view, we get a very different picture of temperature changes, which is discussed in “Temperature changes in Canadian cities: Where’s the scary warming?”