In a recent appearance on Tucker Carlson Tonight, Bill Nye, the celebrity “Science Guy,” declared the “scientific evidence” is “overwhelming” that humans are causing the earth to warm “catastrophically fast.” He insisted this is a “settled point” and a “very serious problem in the next few decades.” Claims to this effect are common among climate change activists, but they are rooted in feeble, misleading evidence that is deflated by a broad range of facts.
Contrary to the views of 24% of voters, the earth is measurably warmer than it was three decades ago. Satellite data and ground-level thermometers both show that the earth’s average temperature has increased by about 0.6 to 0.9 degrees Fahrenheit since the 1980s:
Some people are quick to dismiss any evidence that the earth has warmed, given the track record of deceit and misinformation by global warming alarmists. However, this satellite data was developed and is maintained by John Christy and Roy Spencer, two of the world’s most prominent skeptics of the view that global warming is a serious threat.
This modern warming trend is corroborated by an average global sea level rise of 1.3 inches per decade, as measured via satellites. It is also supported by a worldwide network of tide gauges.
In sum, multiple lines of credible evidence indicate the earth has warmed in recent decades. On the other hand, Christy and Spencer have documented that this warming has been far less than the vast majority of climate models predicted:
Recent Warming in Context
The Intergovernmental Panel on Climate Change (IPCC) is the “leading international body for the assessment of climate change.” Its “work serves as the key basis for climate policy decisions made by governments throughout the world.”
To determine if modern warming “is unusual,” the IPCC has pointed out that “it is essential to place it in the context of longer-term climate variability.” This important and logical statement cuts straight to Nye’s claim that the planet is warming “catastrophically fast.”
Nye also told Carlson that the earth has been warming in “decades and now years” by amounts that would normally occur over “millions of years or let’s say 15,000 years.” Nye emphasized, “It’s the rate, Mr. Carlson, it’s the rate that is such a concern.”
Nye’s claims are based on flimsy cherry-picked data that does not meet basic standards of scientific integrity. Understanding this requires a little background on how scientists place the modern climate in context.
The satellite temperature record only goes back to the late 1970s, and the ground-level thermometer record only extends to the mid-1800s. Thus, scientists use “proxies” to estimate temperatures before this era. Proxies are aspects of nature that respond to climate, such as the widths of tree rings and certain elements in marine sediments.
Typically, proxies are indirect measures of temperature from a very limited number of locations, and hence, they are uncertain and often at odds with one another. This can be seen in the following graph from the latest major IPCC report. It presents the results of various proxy studies that cover the past 2,000 years in the earth’s Northern Hemisphere, which is where most proxy studies have been conducted:
For an obvious reason, scientists call this a “spaghetti” graph. And by picking certain strands of spaghetti from it, one can draw very different conclusions.
Note that the black lines on the right of the graph are not proxy studies. They are modern instrument-measured temperatures, which the IPCC often splices with proxy data. This can be misleading, because much of the proxy data in this graph shows temperatures that are the same or warmer a thousand years ago than in recent years. Adding thick black lines to the end of the graph visually masks that reality.
Two pages after this graph, the IPCC bluntly states that it “remains a challenge” to determine temperatures over the last 2,000 years “due to limitations of spatial sampling, uncertainties in individual proxy records and challenges associated with the statistical methods used to calibrate and integrate multi-proxy information.” These statistical problems also apply to integrating proxies with modern instrument-measured temperatures.
Moreover, a 2011 paper in the journal Annals of Applied Statistics found that:
- “the most comprehensive publicly available database” of “proxies do not predict temperature significantly better than random series generated independently of temperature.”
- “it is not clear that the proxies currently used to predict temperature are even predictive of it at the scale of several decades let alone over many centuries.”
Furthermore, the ClimateGate emails prove that the IPCC was not candid with the public about proxy studies. These emails show IPCC scientists and authors:
- writing, “I know there is pressure to present a nice tidy story as regards ‘apparent unprecedented warming in a thousand years or more in the proxy data’ but in reality the situation is not quite so simple. … I believe that the recent warmth was probably matched about 1000 years ago.”
- proposing to conduct an “honest” study about the “uncertainties” of proxies and then “publish, retire, and don’t leave a forwarding address,” because “what I almost think I know to be the case, the results of this study will show” that we “honestly know f**k-all” (i.e., little or nothing) about temperature changes in the Northern Hemisphere over more than a hundred years.
- creating a diagram of raw proxy data to see if it “provided” an “obvious” picture of “unprecedented warming over the last millennium or so”—and then burying this diagram over concerns that it could “dilute the message about the strength of 20th century mean warming.”
- writing, “I’ve just completed Mike’s Nature trick … to hide the decline.”
The last of these emails exposed how leading IPCC scientists cropped three different proxy series to hide the fact that they show temperature declines in the modern era. These declines directly contradict instrument-measured temperatures.
The author of this email spliced these doctored proxy series with instrument-measured temperatures to make the following chart. It was published with a note stating that “all the reconstructions … indicate that against the background of the millennium as a whole, the 20th century was unusually warm”:
This is the type of deceitfully presented, cherry-picked data that lies behind claims that the current warming is abnormal. Comprehensive, untainted data does not show this. Most importantly, the proxy data does not have nearly enough certainty to be described as “overwhelming” or “settled.”
Local Anecdotes & Global Trends
Near the end of the interview, Carlson asked Nye, “What would the climate look like right now without human activity?” He replied, “It would look like it did in 1750,” and “you could not grow wine-worthy grapes in Britain, as you can today, because the climate is changing.” Nye also rattled off similar claims about French winemakers, ski resorts in Europe, pesticides in the Midwest, and beetles in Wyoming.
Such statements betray gross ignorance of the science of climate change, because local and regional anecdotes often don’t reflect global trends. In the candid words of a 2001 ClimateGate email:
Look at the instrumental record! There are huge differences between different regions—Alaska has warmed substantially while eastern North America cooled after the 1950s. Locking onto local records, no matter how beautiful, can lead to serious errors.
Likewise, the 2007 IPCC report presented the following chart of regional proxy data from three studies to show “the wide spread of values exhibited by the individual records that have been used to reconstruct” temperatures in the Northern Hemisphere:
The IPCC used this chart to explain why “multiple strands of evidence” showing “a period of widespread and generally warmer temperatures” in Western Europe during the Middle Ages doesn’t prove that the entire globe was warmer at this time. The IPCC made this argument despite a “very diverse mixture of” evidence for this warm period, such as “historical information,” “treeline and vegetation changes,” and “records of the cultivation of cereals and vines.”
The IPCC even acknowledged that “considerable areas of Iceland” were cultivated in the 10th century,” Norse settlers colonized Greenland, and “a general absence of sea ice allowed regular voyages at latitudes far to the north of what was possible in the colder 14th century.” Yet, the IPCC concluded that “in medieval times, as now, climate was unlikely to have changed in the same direction, or by the same magnitude, everywhere.” These statements show that by the standards of the IPCC, Nye’s anecdotes don’t prove a thing about global warming.
Ironically, Nye’s claim about wine grapes in Britain is meritless even in a local sense. Archaeological and historical records show that wine grapes were grown in England from about 1000 to 1400 AD. This is roughly the same amount of time from 1750 as we are today, which undercuts Nye’s claim that the earth is now warming in years by amounts that would normally occur over millions or thousands of years. As explained in books that address the topic of wine grapes in Britain:
- “Surviving landscape evidence of cultivation and contemporary documentation show that grapes for wine were grown even as far north as England during the Middle Ages up through the long period of mild climate that lasted until approximately the end of the 14th century, when weather conditions generally deteriorated with lower temperatures and increased dampness crippling agriculture across northern Europe.” – Daily Life in the Middle Ages, page 20.
- “Bede [673–735 AD] states that there were vineyards ‘in some places’ [in England], but it is probable that these remained few until the climate began to warm up in the eighth and ninth centuries. By 1100 to 1200 the climate was more like that of northern France today with summer temperatures generally about 1° C higher than now…. Domesday Book [1086 AD] records the existence of 55 vineyards of all sizes in England.” – The Archaeology of Medieval England and Wales, page 276.
After Nye talked about grapes and beetles, he said “That’s how the world would be different if it weren’t for humans. … I spent a lot of time with this topic.” His statements only reveal that he has spent a lot of time listening to climate change alarmists and very little time conducting genuine research.
Conditions such as growing seasons, rainfall, drought, famine, insect populations, storms, and flooding have varied widely across time and place throughout earth’s history. Hence, there are countless anecdotes that one can use to tell climate stories. That, however, is not science.
Per Webster’s College Dictionary, science is the “systematic knowledge of the physical or material world gained through observation and experimentation.” The key word is “systematic,” and contrary to claims that global warming would:
- cause famines, global vegetation productivity increased by 6.2% between 1982 and 1999.
- decimate the world’s coastlines, the world has actually gained coastal land over the past three decades.
- increase the number and intensity of hurricanes and tropical storms, no such trends are evident for as far back in time as the data extends.
- increase rainfall and flooding, no clear trends are evident for as far back in time as the data extends.
Given these facts and others like them, climate doomsayers often resort to anecdotes. And as with Nye, even these anecdotes sometimes prove to be false.
The So-Called Consensus
Echoing certain journalists, Nye told Carlson it is a “settled point” in “the science community” that global warming will be a “very serious problem in the next few decades.” Such claims generally stem from non-representative polls that ask scientists if humans have contributed to global warming—not if it presents a grave threat.
In contrast, 3,805 people with degrees in atmospheric, earth, or environmental science and 9,029 Ph.D.’s in varying scientific fields, have signed a petition stating:
There is no convincing scientific evidence that human release of greenhouse gasses is causing or will, in the foreseeable future, cause catastrophic heating of the Earth’s atmosphere and disruption of the Earth’s climate.
This does not mean that these individuals represent a majority of scientists or that they are the most informed about this issue. However, it does show substantial dissent among scientists. This directly refutes those who claim that no such debate exists.
There is a lot of posturing about science in the world of politics, but much of what the media reports as “science” is actually partisan propaganda that is refuted by science. The issue of global warming is rife with this, and Nye’s statements epitomize the junk science that has become so prevalent today.
James D. Agresti is the president of Just Facts, a nonprofit institute dedicated to publishing verifiable facts about public policy.
Image Credit: Public Domain