Today’s 1.2 degrees Celsius (2.2 degrees Fahrenheit) average global temperature rise above preindustrial levels is now as warm as any time in the last 10,000 years. It is three times warmer than the average temperature for the last 2,000 years, the period when the Earth systems our advanced civilization depends upon evolved. These systems are things like the Amazon, boreal forests, permafrost, a stable sea level, ice sheets, sea ice and the Gulf Stream. This relatively small amount of warming may not seem like much, but only 5 degrees Celsius (10 degrees Fahrenheit) separates the deepest of Ice-Age cold from our previous climate.
Some of the latest science tells us that half of known climate-tipping systems have activated their collapses since about 2009. A tipping point is crossed when a small change creates a big outcome — like leaning over in a small boat too far and suddenly going for a swim. Fundamentally, Earth’s temperature has risen above the evolutionary boundaries of these systems, and their collapse thresholds have been crossed.
The Amazon rainforest, Canadian forests and global permafrost are three Earth systems now in tipping collapse. They have flipped from carbon sequestration to emissions with greenhouse gas emissions of plausibly seven gigatons per year. This is as much as all global emissions from transportation.
These collapses were activated with warming of 0.5 to 0.75 degrees Celsius (0.9 to 1.3 degrees Fahrenheit) above normal from the late 19th century, when the last 2,000 years our world’s average temperature was no warmer than 0.4 degree Celsius (0.75 degree Fahrenheit) above the late 19th century. But the averages themselves are misleading. For example, warming over land is twice what it is over oceans. High temperatures are another example of why today’s averages are misleading.
For example, in Austin, Texas, where I live, the average high temperatures in September from 2017 to 2020 were 5.3 degrees Fahrenheit warmer than between 1966 and 1969. In other words, the normal high in early September, that was 93 degrees Fahrenheit in our “previous climate” (circa 1900), is 98 degrees Fahrenheit today. One would think this kind of warming would have made the headlines in recent years, but this is not the case, and there is a good reason. The National Weather Service (NWS) has a long-standing and little-known statistical weather data procedure that inadvertently helps promote the denial of global climate disruption.
The “normal” temperatures the NWS reports are averages of the last 30 years. This is the data broadcast on the weather report on the news every night. These so-called normal temperatures are not at all the temperatures from our previous climate. They are not from a time before our climate began to unnaturally warm. What we hear as “normal” from our faithful weather professionals is actually significantly warmer for most of us, has nothing to do with what most of us think of as “normal” and has nothing to do with our previous climate where our advanced civilization evolved.
Going back to my home state as an example, extremely warm temperatures in Texas in December 2021 broke the 1933 monthly average temperature record by an astonishing 4.7 degrees Fahrenheit. Normally, monthly average temperature records are broken by less than a degree or two Fahrenheit in a stable climate; in our previous normal climate. Across Texas, the high temperature was 12 degrees Fahrenheit above the state 20th-century high temperature average for December. Austin’s December average high temperature was 11.5 degrees Fahrenheit above the 30-year normal.
The statistical procedure to change the normal temperature data is known in professional circles as the “30-year normal,” or the climatological normals, but among the public, this weather data is known as our “normal” weather. The reason for this data manipulation began in the 1930s, with agriculture and as the need for historic climate data increased and spread into other industries.
The idea here was to supply agricultural and industrial communities with the latest and most accurate weather data related to temperatures, heat waves, first and last freezes, hours below freezing, peak temperature per day/week/month/year, all sorts of precipitation records, etc. The justification of the NWS for this deliberate manipulation of weather data is, “a better understanding of what is happening today. Rather than assess long-term climate trends, Normals (sic) reflect the impacts of the changing climate on our day-to-day weather experience.”
This strategy of changing the “normal” data for scientific accuracy worked well when our climate was stationary (not changing radically), and when a hugely significant portion of our population needed to know so they could successfully grow food for us all. But today is definitively not like the past. What the NWS is doing by warming the so-called “normal” temperatures hides global climate disruption in the minds of the public. “Normal climate” today is not the average of the last 30 years; it is what our climate was before it began to radically warm.
So, what is “normal” then? Climate science defines two major “normal” periods. One is “pre-industrial times.” This is the period between 1850 and 1900 and is the baseline for our stable climate before we began to massively emit greenhouse gasses. The other period is 1951 to 1980. The National Oceanic and Atmospheric Administration describes this period as that time “when many of today’s adults grew up, so it is a common reference that many people can remember.”
The 2,000 years prior to the pre-industrial period of 1850 to 1900 is quite meaningful. During this 2,000 years, Earth’s temperature was very stable at no warmer than 0.4 degrees Celsius (0.7 degrees Fahrenheit) above the 1850 to 1900 average for almost the entire 2,000 years. This makes our 1.2 degrees Celsius above normal current warming three times warmer than the maximum of the last 2,000 years. This 0.4 degrees Celsius-maximum temperature range represents the upper boundary of the climate where our current Earth systems evolved. It’s also known as the “natural variation” of our climate. It represents the evolutionary boundary of our Earth’s systems.
We have warmed Earth above the evolutionary boundaries of its systems, and they are in collapse so they can re-evolve with species and mechanisms that are tolerant of the new climate. This collapse, or excursion beyond the normal, is evident in the nonlinear increase of climate and weather extremes we have all witnessed or endured recently.
Collapse of these systems is directly related to climate tipping where Earth system collapses result in loss and even reversal of environmental services. Environmental services are things or processes our ecologies or Earth systems supply us with or do for us, like forest products for building materials or oxygen generation from plants. One of the most important and easily degraded environmental services is carbon sequestration, or the ability of our Earth systems to absorb carbon dioxide. This sequestration is reversed with these tipping collapses as we are now seeing in the Amazon, Canadian forests, and permafrost and their plausible emissions of seven gigatons of greenhouse gasses per year. Very importantly, these are just the first system collapses to be studied. Similar systems across the globe are likely in collapse too, and the collapses have just begun.
The public needs to know how much warming has occurred so we can make realistic decisions about climate change. Americans trust weather professionals on climate change. Our television weather persons are the ones that provide the vast majority of us with what is our best and most trustworthy information about climate change. However, through their standard professional procedures, though no fault of their own, they are masking evidence of global climate warming.
Today in Austin, the summer (June through August) five-year average high temperature has warmed 6 degrees Fahrenheit, the 10-year average summer high temperature has warmed 5 degrees Fahrenheit, but the 30-year NWS “normal” has warmed only 1.6 degrees Fahrenheit. This 30-year averaging procedure not only masks warming, it understates it, too.
Think about what this means to the reporting of heat waves. As the NWS warms the “normal” temperatures, the heat wave diminishes in relative extremeness to us poor, sweltering humans, and we don’t even realize that the NWS has created a stifling understatement through their long-held data reporting standards.
There is a valid and urgent need to use a much shorter averaging period. Warming is not going to self-restore, it is only going to continue warming nonlinearly, like it has been doing for the last hundred years.
Our historical normal temperatures (not the NWS “normals”) are from the time when our advanced civilization evolved; they come from the climate that created humankind as we know it. This climate definitively does not include the temperature “normals” of the last 30 years presented by the NWS to broadcast to the entire United States population. Our true normal temperatures are what the temperatures were back in the late-19th century before our greenhouse gas emissions from fossil fuels and land use changes began to substantially warm Earth.
When historic weather statistics are removed from daily weather communications and replaced with statistics that are warmer and warmer every 10 years, the results are that the public’s awareness of global climate disruption is damaged, degraded, or simply erased.
Even more damaging, the same weather person that tells us the current much-warmed temperatures are normal, also tells us that, yes, our climate is warming.
This confusion, imperceptible to almost all of us, creates distrust, disbelief and loss of credibility with our weather professionals. What does this do to the public’s perception of climate change? When our weather people tell us our daily temperatures are normal, then they tell us climate change is a real problem, what are we to believe? How many citizens understand this is going on — that the “normal temperatures” delivered on the weather report every night are not normal? Loss of climate change awareness feeds the narrative that climate change is either not real or is not meaningful.
To see the warming, the public must see the difference between our climate today and our climate in the past.
Today, our population is no longer significantly agrarian-based; nowhere close. In 1900, just under 40 percent of Americans lived on farms; today, around 1 percent live on farms. The industrialists that need this information are an exceedingly small proportion of our population. Those that need this kind of up-to-date weather data can easily get it from the NWS or others, but the rest of us need to know what “normal climate” really means.
The climate has warmed — a lot. It’s not normal. None of it is natural. Most of the warming has been recent, with two-thirds in the last 30 years, and half in the last 20 years, and the rate of warming is still increasing. With this warming comes nonlinearly increasing extremes and Earth systems tipping collapses. The average global temperature today is now three times warmer than the climate where our Earth systems evolved, these systems are now collapsing, and the collapses do not stabilize unless the temperature is lowered to below the tipping threshold.
When there is no threat of irreversible and societally decimating scenarios from an artificially warmed climate, sure, recalculate the normals. But when awareness of global warming is more critical than ever before, this practice of recalculating the normals is existentially dangerous.
It is now profoundly important this policy of changing the “normals” be eliminated. The NWS is purposefully warming the normal temperature statistics as our climate warms. They are doing this because it is a habit from the past; a habit whose time must come to end.
A longer version of this article appears at Climate Discovery.