Statistically, it's growing warmer.
Recently, as I was working with a spreadsheet that has all of my weather forecasts for The Old Farmer’s Almanac for the 23 years that I have been making them, it occurred to me that here was a database that contains a great deal of information that might be useful in looking at trends.
To do this, I moved the data around within the spreadsheet to be able to create graphs showing how temperatures have changed over the past 23 years. These graphs show some interesting trends that seem to fit, at least in a general sense, with the idea that it’s growing warmer.
Above-Normal Temperature “Normals”
Let me explain these graphs. As you may realize, each year we forecast the coming year’s weather for 18 United States regions and seven Canadian ones. The maps of these regions that appear in The Old Farmer’s Almanac print editions and on Almanac.com show several cities within each; it is these cities for which I have compiled data on actual temperatures and how they have departed from normal.
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For example, when I say that the temperature departure for December 2018 was 2.61 degrees F (see Figure 1, below), this means that the average of all of the cities shown on all of these regional maps for the United States and Canada was 2.61 degrees F warmer than their most recent official 30-year normals, which cover the period of 1981–2010. The “normal temperatures” that I use are the official ones updated once each decade by the United States and Canadian government meteorological services, based upon smoothed averages of daily temperatures for the 30-year period covered.
Figure 1. Monthly temperature departures from normal, 1996–2018.
Thus, if I say that the 2019 average temperature is 1 degree above normal, this temperature is going to be different from what it would be if I were referring to the 2009 average temperature being 1 degree above normal, because over the ensuing decade the “normal” temperatures would have been recalculated and changed.
Since temperatures generally have been rising, this means that each decade, when the new “normal” temperatures are computed, they are higher than the previous “normal” temperatures. The effect of this is that a graph that shows how temperatures have departed from normal over the years actually understates the real increase in temperatures, since the normals are rising along with the actual temperatures.
When we examine the graph showing the monthly departure of temperature from normal (Figure 1, above), we see that most—but not all—months in the past 23 years have had temperatures above normal. However, there does not seem to be any clear trend in these temperature departures, or at least not one that I can readily see. The greatest positive departure was 8.67 degrees F back in January 2006, while the greatest negative departure was 4.78 degrees F in December 2000.
Figure 2. 12-month moving average of monthly temperature departures from normal, 1996–2018.
When we look at the 12-month moving average of these departures (Figure 2, above), their pattern becomes more apparent, as there does seem to be a general rising trend in the temperature departures, with nearly all above normal. The only times when this 12-month moving average of temperature departures for the United States and Canada were below normal were in 2001 and 2014.
Figure 3. 36-month moving average of monthly temperature departures from normal, 1996–2018.
Examining the 36-month moving average of temperature departures (Figure 3, above) seems to show a trend emerging. Although there are still peaks and valleys, a general upward trend seems more apparent, with each peak higher than the previous one.
What Causes these Changes?
Meteorologists and climatologists have proposed various explanations for the month-to-month and annual variations, including teleconnections such as El Niño, changes in ocean currents, and changes in solar output.
As for the clear trend of rising temperatures over the past decades, I have seen only three viable proposed explanations: (1) natural variability (perhaps combined with changes in land use and population), (2) an expected general rise in average temperatures as we are still coming out of the last ice age, and (3) warming temperatures due to human activities that increase the levels of carbon dioxide and other atmospheric greenhouse gases.
Find predicted temperatures for the upcoming year in The 2019 Old Farmer’s Almanac.
Michael Steinberg
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I note when people like to think the planet is warming that there is little to any consideration given to the rising population. The increase of population in cities naturally increase temperature. Because of all the hard surfaces and the continual reduction of greenery. Even in small towns the temperature difference from farm to town where the temperatures are often recorded can be 3 degrees or more in difference a somewhat large amount. As most towns and cities around the world grow it is only natural to see records being broken because of where most records are taken. Secondly much of the temperature data taken for rural and remote locations has been done so for such a short period of time we don't have a reasonable data point to say the planet is warming. Thirdly why do people want to be so concerned about Carbon after all if there is not enough of it the plants will die and so will we. so common stop listening to global warming hoax as if it was a bad thing. In a greenhouse we can add Carbon dioxide to increase plant growth. We really need more of it not less so that the water cycle can operate properly and we can grow more food for our ever growing population. All science 101 stuff the so called scientists seem to conveniently forget. Why?
Thank you Dale. A voice of reason in the madding crowd.
See, this is what gets me about climate deniers. We, average, ordinary people, can chart the data ourselves and see, without a doubt, that the climate is warming. So, when 97% of the people who have literally spent their whole lives studying this say it's true, and we can see ourselves that it's true, how can you possibly deny it? When literally ALL of the evidence points to it, how can anyone deny it?
We don't deny that the days are getting warmer. We deny the unproven reasons that are given. One specific action does not necessarily result in a certain reaction. For instance, there is marketing data that shows ice cream sales increase during the summer. The is also criminal data that shows crime increases during the summer. So, can we automatically deduce that if we ban ice cream sales in the summer, then crime will decrease? Of course not! But that is how climate change, a.k.a. global warming, has been deduced. You must prove that ice cream sales directly influences crime. You can't just say it, or assume it, and it be true.
You are confusing two things: the existence of global warming, and the assertion that it is mostly or entirely due to human activity. Even many skeptics agree that there has been some warming, but they also note - from the data - that it depends on the time frame you choose to examine. They may disagree on the amount, and they diverge sharply on the question of causation and on the recommended actions.
I am quite certain that if you choose to dismiss all skeptics as "deniers" - a religious term, not a scientific one - then you will indeed conclude that every "reputable" scientist thinks it's all our fault, and unless we take drastic action - action which always seems to exempt certain people - we are headed for the apocalypse. You might want to source the often-cited "97%" figure, though: it was taken from a survey of the literature, using rather loose criteria, and many of the scientists whose work was referenced have subsequently stated that their papers did not support the conclusions the survey attributed to them. Moreover, another way to interpret the data, from that same survey, is that about ONE percent of scientists drew that conclusion.
I hesitate to introduce calm deductive logic into so passionate a discussion, but allow me to present just a little. In case you aren't familiar with the term "syllogism", it is (from Wikipedia) "a kind of logical argument that applies deductive reasoning to arrive at a conclusion based on two or more propositions that are asserted or assumed to be true."
Here is the global warming syllogism as I often hear it:
(P1) Global warming is real;
(Conclusion) Therefore, we need to make significant - even drastic - changes in our lifestyle, to prevent a catastrophe.
The problem is that the stated Conclusion is not supported by that Proposition - in other words, the argument is irrational. Here is the valid syllogism:
(P1) Global warming is real.
(P2) Global warming is caused primarily by human activity.
(P3) The effects of global warming are predominantly or exclusively negative (or catastrophic).
(P4) Global warming can be substantially mitigated, halted, or reversed by changes in human activity.
(P5) The proposed changes in human activity do not produce other, equally negative consequences.
(P6) The proposed changes in human activity are acceptable to the human population.
(Conclusion) Therefore, it makes sense to call for significant - even drastic - changes in our lifestyle.
My analysis of the whole argument runs to 12 pages, and I am sure you won't want to read it, because I am clearly an ignorant heretic who deserves to be stoned to death - or at least silenced.
some people argue that its explanation 1 and 2, not 3 and therefore "not our problem"
And they have a somewhat valid point. The data shows warming, it cannot show the cause of the warming. There is some interesting data showing correlation between carbon emissions and temperature rise--but even then it doesn't establish a causation. This same problem came up when we started noticing trends in smoking and lung cancer. The trend was there, but the only way to prove causation would be to carry out an experiment were some randomly chosen people smoke and a control group does not and see if the smokers get more cancer.
Most scientist (all but a very small handful) agree that it is human caused because of the accompanying trends (like carbon emissions).
Having had a look at your graphs, and they do show a general warming trend, makes me wonder that if similar studies were done throughout the Northern Hemisphere and the Southern Hemisphere, we would see the way the North Pole is tilting so much away from where it was known to be for the last centuries - the Polar shift is becoming more pronounced and because of this, certain areas appear to be and indeed, are becoming warmer. So we shouldn't blame it all on global warming, blame it on Polar Shift. One of these fine days, in the next 1000 or two years time, kerboom, a new ice age.
I think you might be mistaken on what the "polar shift" is. It's a magnetic shift, not a physical one. The Earth's magnetic field plays absolutely no role in climate or weather.
In recent years the effect of the movements of molten materials within the core of the planet and more particularly closer to the surface have been being studied. From the early results of these studies it would appear there is a correlation between these movements and climate changes. Therefore I think your categoric debunking That the magnetic pole change doesn't affect climate somewhat unwise. True science fact can only be established by being able to perform the same experiment over and over again and always get the same answer. That fact only apples when the same conditions are used. Most of what is said to be scientific today, appears to me to be science fiction.
Having had a look at your graphs, and they do show a general warming trend, makes me wonder that if similar studies were done throughout the Northern Hemisphere and the Southern Hemisphere, we would see the way the North Pole is tilting so much away from where it was known to be for the last centuries - the Polar shift is becoming more pronounced and because of this, certain areas appear to be and indeed, are becoming warmer. So we shouldn't blame it all on global warming, blame it on Polar Shift. One of these fine days, in the next 1000 or two years time, kerboom, a new ice age.
