By Paul Homewood
The Federal Climate Science Special Report from the US Global Change Research Program, mandated under the U.S. Global Change Research Act of 1990, has now been published.
As with the draft, which I reported on in August, it is the usual mix of half truths, exaggerations, omissions and outright lies.
Let’s look at the main sections:
1) Global Temperatures
The global, long-term, and unambiguous warming trend has continued during recent years. Since the last National Climate Assessment was published, 2014 became the warmest year on record globally; 2015 surpassed 2014 by a wide margin; and 2016 surpassed 2015. Sixteen of the warmest years on record for the globe occurred in the last 17 years (1998 was the exception). (Ch. 1; Fig. ES.1)
These claims are based on surface datasets, which are extremely patchy and affected by urbanisation:
But according to the much more comprehensive satellite data, global temperatures last year were statistically the same as in 1998.
The Report goes on to project large temperature increases during the 21stC of up to 5C. Yet it ignores the fact that the computer models on which these forecasts are made have consistently overestimated warming since 1980.
2) US Temperature Trends
Annual average temperature over the contiguous United States has increased by 1.8°F (1.0°C) for the period 1901–2016 and is projected to continue to rise
This claim is highly dubious.
As the Report itself admits:
In the United States, the urban heat island effect results in daytime temperatures 0.9°–7.2°F (0.5°–4.0°C) higher and nighttime temperatures 1.8°– 4.5°F (1.0°–2.5°C) higher in urban areas than in rural areas.
The UHI effect has undoubtedly increased since 1901, yet far from adjusting temperatures to reflect this, NOAA have actually done the opposite, and cooled the past:
3) US Temperature Extremes
There have been marked changes in temperature extremes across the contiguous United States. The number of high temperature records set in the past two decades far exceeds the number of low temperature records.
The frequency of cold waves has decreased since the early 1900s, and the frequency of heat waves has increased since the mid-1960s (the Dust Bowl era of the 1930s remains the peak period for extreme heat in the United States).
This is one of the most dishonest sections of the whole Report.
First, let’s look at the daily temperature records claim:
These records are based on GHCN data, where large numbers of US stations only have data back to around 1960. Given that the 1960s and 70s were particularly cold decades in the US, it is hardly surprising that high daily records have dominated low ones in the last couple of decades.
Worse still, many of the GHCN stations should not be used for climatic purposes, such as airports.
USHCN stations are a much higher quality and long running dataset, and analysis of these consistently show that most daily highs occurred during the 1930s.
The Report goes on to claim that the frequency of heat waves has increased since the mid-1960s .
I wonder why they chose to start from the 1960s?
Hidden away in Chapter Six of the main report, on page 191, lies the dirty secret that they have done their best to hide. (Readers may recall that this “secret” was originally in the Draft Executive Summary, but was taken out as it was far too embarrassing).
Cold extremes have become less severe over the past century. For example, the coldest daily temperature of the year has increased at most locations in the contiguous United States (Figure 6.3).
Changes in warm extremes are more nuanced than changes in cold extremes. For instance, the warmest daily temperature of the year increased in some parts of the West over the past century (Figure 6.3), but there were decreases in almost all locations east of the Rocky Mountains. In fact, all eastern regions experienced a net decrease (Table 6.2), most notably the Midwest (about 2.2°F [1.2°C]) and the Southeast (roughly 1.5°F [0.8°C]). The decreases in the eastern half of Nation, particularly in the Great Plains, are mainly tied to the unprecedented summer heat of the 1930s Dust Bowl era, which was exacerbated by land-surface feedbacks driven by springtime precipitation deficits and land mismanagement. However, anthropogenic aerosol forcing may also have reduced summer temperatures in the Northeast and Southeast from the early 1950s to the mid-1970s, and agricultural intensification may have suppressed the hottest extremes in the Midwest. Since the mid-1960s, there has been only a very slight increase in the warmest daily temperature of the year (amidst large interannual variability).
Take particular note of the bottom two graphs of Figure 6.4. There has certainly been a rise in the number of warm days and the heat wave index since the cold 1960s, but heat waves were much more common in earlier decades.
The inference that the dustbowl era was a one off event is also misleading. High summer temperatures were also commonplace both before the 1930s, and notably during the 1950s. Heatwaves now are no more intense than in the early 1900s.
The simple truth is that, over the full period, the coldest days have become milder, while the hottest ones have grown less hot. Put another way, the US climate has become much less extreme than it used to be.
For some reason, the authors did not want to show this in the Executive Summary.
4) US Droughts
Recent droughts and associated heat waves have reached record intensity in some regions of the United States; however, by geographical scale and duration, the Dust Bowl era of the 1930s remains the benchmark drought and extreme heat event in the historical record
Another highly disingenuous claim. As NOAA themselves show, droughts were much more severe and frequent not only in the 1930s, but in the 1950s as well.
Indeed, prior to the 1970s, drought years were the norm.
5) US Precipitation
Heavy precipitation events in most parts of the United States have increased in both intensity and frequency since 1901
In fact, heavier rainfall is simply the other side of the coin of intense droughts.
The Report claims that “Extreme precipitation events will very likely continue to increase in frequency”
But NOAA themselves show that rainfall trends have changed little since the 1970s.
The Report also implies that heavier rainfall will lead to more floods. But the USGS put that nonsense to bed in 2012, when their report found:
The coterminous US is divided into four large regions and stationary bootstrapping is used to evaluate if the patterns of these statistical associations are significantly different from what would be expected under the null hypothesis that flood magnitudes are independent of GMCO2. In none of the four regions defined in this study is there strong statistical evidence for flood magnitudes increasing with increasing GMCO2.
6) Sea Level Rise
Global mean sea level (GMSL) has risen by about 7–8 inches (about 16–21 cm) since 1900, with about 3 of those inches (about 7 cm) occurring since 1993
The implication is that sea level rise is accelerating, leading to wild claims of a rise of 4 feet by 2100.
The facts show a totally different situation. As even the IPCC had to admit, sea level rise between 1920 and 1950 was similar to the recent period.
Sea levels have been rising steadily since the mid 1800s, with a slow down in between around 1960 and 1990.
There is no evidence at all that sea level rise is accelerating. There was a huge expansion in glaciers worldwide during the LIA, culminating in the 19thC.
They began retreating as early as the late 18thC, and at faster rates than in recent years, but evidence suggests that they are still more extensive than in the Middle Ages.
Most of the sea level rise since then is the result of that perfectly natural process.
7) Arctic Temperatures
Annual average near-surface air temperatures across Alaska and the Arctic have increased over the last 50 years at a rate more than twice as fast as the global average temperature
Again, one has to ask why they start from such a cherry picked date, when the Arctic was entering a much colder interlude.
As HADCRUT data shows, temperatures across the Arctic were just as high as now in the 1930s and 40s.
It is well accepted that Arctic temperatures follow the AMO cycle, which is currently in warm phase.
Astonishingly, I have searched the Executive Summary, and there is not a single mention of the AMO. This is utterly dishonest.
8) Arctic Sea Ice
Since the early 1980s, annual average arctic sea ice has decreased in extent between 3.5% and 4.1% per decade, has become thinner by between 4.3 and 7.5 feet, and is melting at least 15 more days each year. September sea ice extent has decreased between 10.7% and 15.9% per decade
These deceitful statements keep piling up, don’t they?
Yet as their own graph shows, the downward trend ended in 2007, since when sea ice extent has stabilised.
And as already noted, they begin their graph in 1979, after some of the coldest years in the Arctic on record.
Tornado activity in the United States has become more variable, particularly over the 2000s, with a decrease in the number of days per year with tornadoes and an increase in the number of tornadoes on these days
This is a particularly mealy mouthed statement, which attempts to hide the actual facts.
The claim of an increase in the number of tornadoes on these days, is in fact a fake one. As NOAA’s tornado scientists readily admit, many more tornadoes are reported nowadays because of advances in technology, such as Doppler radar, which only became widespread in the late 1990s.
As they also make clear, there has been a drastic reduction in strong tornadoes since the 1970s.
Both theory and numerical modelling simulations generally indicate an increase in tropical cyclone (TC) intensity in a warmer world, and the models generally show an increase in the number of very intense TCs. For Atlantic and eastern North Pacific hurricanes and western North Pacific typhoons, increases are projected in precipitation rates (high confidence) and intensity (medium confidence). The frequency of the most intense of these storms is projected to increase in the Atlantic and western North Pacific (low confidence) and in the eastern North Pacific (medium confidence).
Yet, as the main Report goes on to reveal (on page 263!), there has been no detectable trend in tropical cyclone intensity.
Despite a busy Atlantic hurricane season this year, there is still no evident trend in global tropical cyclone activity since the start of the satellite era:
This year there have been six major Atlantic hurricanes, but NOAA’s Hurricane Research Division shows this is not unusual. The highest number recorded was eight in 1950.
Again there has been no apparent trend since regular monitoring of hurricanes began with hurricane hunter aircraft in the mid 1940s.
The dip in activity during the 1970s and 80s is clearly linked to the cold phase of the AMO, a connection which is well established scientifically.
Steve Koonin, Under Secretary for Science during President Obama’s first term, also finds the Report misleading, writing in an article for the Wall Street Journal:
The world’s response to climate changing under natural and human influences is best founded upon a complete portrayal of the science. The U.S. government’s Climate Science Special Report, to be released Friday, does not provide that foundation. Instead, it reinforces alarm with incomplete information and highlights the need for more-rigorous review of climate assessments.
A team of some 30 authors chartered by the U.S. Global Change Research Program began work in spring 2016 on the report, “designed to be an authoritative assessment of the science of climate change.” An early draft was released for public comment in January and reviewed by the National Academies this spring. I, together with thousands of other scientists, had the opportunity to scrutinize and discuss the final draft when it was publicized in August by the New York Times . While much is right in the report, it is misleading in more than a few important places.
One notable example of alarm-raising is the description of sea-level rise, one of the greatest climate concerns. The report ominously notes that while global sea level rose an average 0.05 inch a year during most of the 20th century, it has risen at about twice that rate since 1993. But it fails to mention that the rate fluctuated by comparable amounts several times during the 20th century. The same research papers the report cites show that recent rates are statistically indistinguishable from peak rates earlier in the 20th century, when human influences on the climate were much smaller. The report thus misleads by omission.
This isn’t the only example of highlighting a recent trend but failing to place it in complete historical context. The report’s executive summary declares that U.S. heat waves have become more common since the mid-1960s, although acknowledging the 1930s Dust Bowl as the peak period for extreme heat. Yet buried deep in the report is a figure showing that heat waves are no more frequent today than in 1900.
Such data misrepresentations violate basic scientific norms. In his celebrated 1974 “Cargo Cult” lecture, the late Richard Feynman admonished scientists to discuss objectively all the relevant evidence, even that which does not support the narrative. That’s the difference between science and advocacy.
These deficiencies in the new climate report are typical of many others that set the report’s tone. Consider the different perception that results from “sea level is rising no more rapidly than it did in 1940” instead of “sea level rise has accelerated in recent decades,” or from “heat waves are no more common now than they were in 1900” versus “heat waves have become more frequent since 1960.” Both statements in each pair are true, but each alone fails to tell the full story.
This new climate report is not an objective or an honest assessment of the state of the climate, particularly in relation to the US.
Instead, it is a highly partisan and politicised report, designed to promote alarmism.
There has been much talk of the need for red and blue teams, to challenge lazy consensus.
It is now time for this to happen, so that this Report can be constructively assessed and, where appropriate, criticised. One of the tasks of a counter group should be to produce their own state of the climate assessment.
The climate mafia have had it their own way for far too long.