- The Myth and Its Flaw
- Context and Analysis
- Posts Providing Further Information and Analysis
- References
This is the "main version" of this post, which means that this post lacks most of my references and citations. If you would like a more comprehensive version with all the references and citations, then please go to the "+References" version of this post.
References are cited as follows: "[#]", with "#" corresponding to the reference number given in the References section at the end of this post.
1. The Myth and Its Flaw
The myth states that there has been, or would be, no warming over or within the past two decades.
Purveyors of this myth include Christopher Monckton, Willie Soon, David Legates, John Christy, Ted Cruz, Scott Pruitt, James Delingpole, Peter Ferrara, Clive Best, Dennis Avery, David Archibald, Anthony Watts, Patrick Michaels, Paul (Chip) Knappenberger, Fritz Vahrenholt, Sebastian Lüning, Judith Curry (Curry also predicts no near-future warming for decades), DocMartyn on Judith Curry's blog, David J. Pristash of the Principia Scientific International blog, Bob Tisdale, William Gray, Don Easterbrook, Habibullo Abdussamatov, Nils-Axel Mörner, François Gervais, Joachim Seifert, Frank Lemke, Girma Orssengo, Carl-Otto Weiss, Dietrich Koelle, Herbert Grubel, Pat Frank, Ira Glickstein, Leonid B. Klyashtorin, Alexey A. Lyubushin, Yanjun Mao, Jiqing Tan, Bomin Chen, Huiyi Fan, Cliff Ollier, Scott Armstrong, Richard Lindzen, Sherwood Idso, Ole Humlum (who runs the contrarian blog Climate4You), Jan-Erik Solheim, Kjell Stordahl, Nicola Scafetta, Craig Loehle, Syun-Ichi Akasofu (some of Akasofu's own defenders admit he under-estimated warming), Norman J. Page, Qing-Bin Lu, Matt Ridley, Ian Plimer, Thayer Watkins, Alan Rudge, Anastasios Tsonis, Joseph D'Aleo, Dan Pangburn, Warren Meyer, and Joe Bastardi (Bastardi claims a decade of cooling for 2011 - 2021, and thus his claim is not yet falsified, though post-2011 trends so far suggest his claim will likely fail, as shown in section 2). I discuss some of these myth proponents' debunked temperature trend predictions in a separate multi-tweet Twitter thread [11], with a separate thread that also rebuts Curry's claims [12].
(All of these myth proponents also run afoul of the quantified post-1997 and post-1998 surface warming trends in section 2.1 of "Myth: The IPCC's 2007 ~0.2°C/decade Model-based Projection Failed and Judith Curry's Forecast was More Reliable").
The following blogposts and Twitter threads provide numerous examples of temperature trend predictions, including false predictions of no global warming:
- https://twitter.com/AtomsksSanakan/status/1066223748037128192
- https://twitter.com/AtomsksSanakan/status/1074861836086992896
- sections 1 and 2.1 of "Myth: The IPCC's 2007 ~0.2°C/decade Model-based Projection Failed and Judith Curry's Forecast was More Reliable"
- sections 1 and 2.1 of "Myth: The IPCC's 1990 Report Over-estimated Greenhouse-gas-induced Global Warming"
- section 2.5 and 2.10 of "Myth: Attributing Warming to CO2 Involves the Fallaciously Inferring Causation from a Mere Correlation"
The myth's flaw: over the past two decades, the near-surface air above ocean and land warmed, as has the lower atmosphere. Other indirect measures, such as melting ice, sea level rise acceleration, increasing geopotential height due to thermal expansion of the lower atmosphere, and increases in temperature extremes, indicated warming as well. This warming was reflected in the difference between the amount of energy Earth takes up vs. the amount of energy Earth release, as indicated by continued warming of deeper ocean regions. Ocean warming is the main metric of note, since ~90% of the excess energy goes into warming the oceans.
One should expect future contrarians/denialists to continue abusing anomalously warm years in order to avoid acknowledging the magnitude of human-made global warming. Take the example of an ocean cycle known as the El Niño Southern Oscillation (ENSO), with its warm El Niño phase and cool La Niña phase. Future contrarians/denialism will likely continue doing at least one of the following:
The myth states that there has been, or would be, no warming over or within the past two decades.
Purveyors of this myth include Christopher Monckton, Willie Soon, David Legates, John Christy, Ted Cruz, Scott Pruitt, James Delingpole, Peter Ferrara, Clive Best, Dennis Avery, David Archibald, Anthony Watts, Patrick Michaels, Paul (Chip) Knappenberger, Fritz Vahrenholt, Sebastian Lüning, Judith Curry (Curry also predicts no near-future warming for decades), DocMartyn on Judith Curry's blog, David J. Pristash of the Principia Scientific International blog, Bob Tisdale, William Gray, Don Easterbrook, Habibullo Abdussamatov, Nils-Axel Mörner, François Gervais, Joachim Seifert, Frank Lemke, Girma Orssengo, Carl-Otto Weiss, Dietrich Koelle, Herbert Grubel, Pat Frank, Ira Glickstein, Leonid B. Klyashtorin, Alexey A. Lyubushin, Yanjun Mao, Jiqing Tan, Bomin Chen, Huiyi Fan, Cliff Ollier, Scott Armstrong, Richard Lindzen, Sherwood Idso, Ole Humlum (who runs the contrarian blog Climate4You), Jan-Erik Solheim, Kjell Stordahl, Nicola Scafetta, Craig Loehle, Syun-Ichi Akasofu (some of Akasofu's own defenders admit he under-estimated warming), Norman J. Page, Qing-Bin Lu, Matt Ridley, Ian Plimer, Thayer Watkins, Alan Rudge, Anastasios Tsonis, Joseph D'Aleo, Dan Pangburn, Warren Meyer, and Joe Bastardi (Bastardi claims a decade of cooling for 2011 - 2021, and thus his claim is not yet falsified, though post-2011 trends so far suggest his claim will likely fail, as shown in section 2). I discuss some of these myth proponents' debunked temperature trend predictions in a separate multi-tweet Twitter thread [11], with a separate thread that also rebuts Curry's claims [12].
(All of these myth proponents also run afoul of the quantified post-1997 and post-1998 surface warming trends in section 2.1 of "Myth: The IPCC's 2007 ~0.2°C/decade Model-based Projection Failed and Judith Curry's Forecast was More Reliable").
(All of these myth proponents also run afoul of the quantified post-1997 and post-1998 surface warming trends in section 2.1 of "Myth: The IPCC's 2007 ~0.2°C/decade Model-based Projection Failed and Judith Curry's Forecast was More Reliable").
- https://twitter.com/AtomsksSanakan/status/1066223748037128192
- https://twitter.com/AtomsksSanakan/status/1074861836086992896
- sections 1 and 2.1 of "Myth: The IPCC's 2007 ~0.2°C/decade Model-based Projection Failed and Judith Curry's Forecast was More Reliable"
- sections 1 and 2.1 of "Myth: The IPCC's 1990 Report Over-estimated Greenhouse-gas-induced Global Warming"
- section 2.5 and 2.10 of "Myth: Attributing Warming to CO2 Involves the Fallaciously Inferring Causation from a Mere Correlation"
The myth's flaw: over the past two decades, the near-surface air above ocean and land warmed, as has the lower atmosphere. Other indirect measures, such as melting ice, sea level rise acceleration, increasing geopotential height due to thermal expansion of the lower atmosphere, and increases in temperature extremes, indicated warming as well. This warming was reflected in the difference between the amount of energy Earth takes up vs. the amount of energy Earth release, as indicated by continued warming of deeper ocean regions. Ocean warming is the main metric of note, since ~90% of the excess energy goes into warming the oceans.
One should expect future contrarians/denialists to continue abusing anomalously warm years in order to avoid acknowledging the magnitude of human-made global warming. Take the example of an ocean cycle known as the El Niño Southern Oscillation (ENSO), with its warm El Niño phase and cool La Niña phase. Future contrarians/denialism will likely continue doing at least one of the following:
One should expect future contrarians/denialists to continue abusing anomalously warm years in order to avoid acknowledging the magnitude of human-made global warming. Take the example of an ocean cycle known as the El Niño Southern Oscillation (ENSO), with its warm El Niño phase and cool La Niña phase. Future contrarians/denialism will likely continue doing at least one of the following:
- cherry-pick temperature trends that have an El Niño at (or soon after) their beginning, and/or have a La Niña at (or soon before) their end, in order to claim global warming paused, stopped, etc.
- if a temperature trend ends on an El Niño year, claim the warming trend is just due to El Niño or some other non-human-made factor
- focus on shorter-term temperature trend fluctuations, instead of longer-term, multi-decadal time-scales at which the effect of human-made greenhouse-gas-induced warming becomes more apparent
- cherry-pick temperature trends that have an El Niño at (or soon after) their beginning, and/or have a La Niña at (or soon before) their end, in order to claim global warming paused, stopped, etc.
- if a temperature trend ends on an El Niño year, claim the warming trend is just due to El Niño or some other non-human-made factor
- focus on shorter-term temperature trend fluctuations, instead of longer-term, multi-decadal time-scales at which the effect of human-made greenhouse-gas-induced warming becomes more apparent
Note that contrarians will likely use these strategies to emphasis periods where ENSO and/or other forms of natural variability temporarily decelerate a global warming trend, while conveniently downplaying times at which this natural variability temporarily accelerates the trend.
I address strategy 1 in this blogpost, along with in section 3.4 of "John Christy, Climate Models, and Long-term Tropospheric Warming" and https://twitter.com/AtomsksSanakan/status/998042024204013568. I also discuss strategy 2 in "Myth: El Niño Caused Post-1997 Global Warming".
Note that contrarians will likely use these strategies to emphasis periods where ENSO and/or other forms of natural variability temporarily decelerate a global warming trend, while conveniently downplaying times at which this natural variability temporarily accelerates the trend.
I address strategy 1 in this blogpost, along with in section 3.4 of "John Christy, Climate Models, and Long-term Tropospheric Warming" and https://twitter.com/AtomsksSanakan/status/998042024204013568. I also discuss strategy 2 in "Myth: El Niño Caused Post-1997 Global Warming".
I address strategy 1 in this blogpost, along with in section 3.4 of "John Christy, Climate Models, and Long-term Tropospheric Warming" and https://twitter.com/AtomsksSanakan/status/998042024204013568. I also discuss strategy 2 in "Myth: El Niño Caused Post-1997 Global Warming".
2. Context and Analysis
The near-surface air above oceans and land warmed over the past two decades. Satellite and weather balloon (radiosonde) analyses also revealed warming of the troposphere, a lower region of the atmosphere where much of Earth's weather occurs. Indirect measures, such as melting ice, sea level rise acceleration, increasing geopotential height due to thermal expansion of the lower atmosphere, and increases in temperature extremes, pointed to warming as well. These two decades of warming were reflected in Earth's energy balance, a measure of the amount of energy Earth takes up vs. the amount of energy Earth releases; continued warming of the deeper ocean reflects this energy imbalance, since ~90% of the excess energy goes into warming the oceans.
The figures below illustrate some of this recent warming:
The near-surface air above oceans and land warmed over the past two decades. Satellite and weather balloon (radiosonde) analyses also revealed warming of the troposphere, a lower region of the atmosphere where much of Earth's weather occurs. Indirect measures, such as melting ice, sea level rise acceleration, increasing geopotential height due to thermal expansion of the lower atmosphere, and increases in temperature extremes, pointed to warming as well. These two decades of warming were reflected in Earth's energy balance, a measure of the amount of energy Earth takes up vs. the amount of energy Earth releases; continued warming of the deeper ocean reflects this energy imbalance, since ~90% of the excess energy goes into warming the oceans.
The figures below illustrate some of this recent warming:
Figure 4: Global, annual, mean surface temperature relative to mean temperature from 1961 - 1990 [8, figure 1b]. I discuss the temperature trend (especially from the 1940s to the 1970s) in the context of a near-linear carbon-dioxide-induced warming trend, in sections 2.6 and 2.10 of "Myth: Attributing Warming to CO2 Involves the Fallaciously Inferring Causation from a Mere Correlation". Other sources offer a similar depiction, but with the addition of four more analyses, including an analysis from the Japanese Meteorological Association (JMA). The JMA provides a post-1890 land+ocean analysis with less global coverage, while the China Meteorological Agency (CMA) also provides a post-1900 global land analysis, as do others, including for the post-1983 period. The CMA recently provided a post-1900 global land+ocean analysis well. Other ocean temperatures analyses exist, confirming recent warming as well. The above figure includes neither the CMA analysis nor the JMA analysis, but both analyses show a similar pattern of 1900s - 1940s warming, temperature stagnation or slight cooling from the 1940s - 1960s, and post-1960s warming. This figure may overestimate 1940s - 1970s cooling due to uncertainties tied to changes in temperature monitoring practices during World War II, as I discuss in "Myth: Karl et al. of the NOAA Misleadingly Altered Ocean Temperature Records to Increase Global Warming. |
Figure 7: Global lower tropospheric temperature trend up to 2017, as estimated by various re-analyses that include data from diverse sources, radiosonde-based (weather-balloon-based) analyses, and satellite-based analyses. The colored lines indicate temperature relative to a baseline of 1981 - 2010 [9, page S17]. The satellite-based analyses likely under-estimate lower tropospheric warming over the past two decades, as admitted by the RSS satellite-based team. I discuss this further in section 2.2 of
"Myth: Evidence Supports Curry's Claims Regarding Satellite-based Analyses and the Hot Spot". |
"Rather, the data are fully consistent with a steady global warming trend since the 1970s, superimposed with random, stationary, short-term variability. All recent variations in short-term trends are well within what was to be expected, based on the observed warming trend and the observed variability from the 1970s up to the year 2000.
[...]
Our purpose has been to determine what can and cannot be said about trends and their changes, based on the temperature data records only. We find that the public discussion of time intervals within the range 1998–2014 as somehow unusual or unexpected, as indicated by terms like 'hiatus', 'pause' and 'slowdown', has no support in rigorous study of the temperature data [emphasis added] [7]."
"The importance of differing definitions of a “hiatus” was discussed in Medhaug et al. [...] where contradictory conclusions can arise in the literature based on the definition. Consequently, elucidating the various different definitions of “pause” or “hiatus” is important.
Among the common definitions of pause/hiatus are: (1) a statistically significant change in the rate of global warming, as measured by changes to the heat balance of the planet; (2) a statistically significant change in the surface temperature record; (3) a non-statistically significant change in the rate of GMST [global mean surface temperature] change; and (4) Divergence between GMST predictions (from climate modes) and actual GMST measurements. Unfortunately, these definitions are often conflated and their separate identities must be maintained.
Among the common definitions of pause/hiatus are: (1) a statistically significant change in the rate of global warming, as measured by changes to the heat balance of the planet; (2) a statistically significant change in the surface temperature record; (3) a non-statistically significant change in the rate of GMST [global mean surface temperature] change; and (4) Divergence between GMST predictions (from climate modes) and actual GMST measurements. Unfortunately, these definitions are often conflated and their separate identities must be maintained.
So, has there been a pause in global warming? The answer would be mistakenly “yes” only if one defines the “global warming” only by GMST changes (definition 3 above) [emphasis added] [13]."
Other studies yielded similar results. As shown in figures 4, 7, 10, 11, and other sources, Earth is in the midst of a global warming trend over 50 years long, extending back to around 1965 and continuing past 1998 to the present. And while the myth falsely claims that the post-1997 time-period constitutes a pause/hiatus in which no global warming occurring, global surface warming instead accelerated, as per figure 12 below (the 2017 paper quoted above [7] excludes recent years of warming, along with excluding various datasets, and thus fails to detect this warming acceleration):
Figure 12: Relative global surface temperature trend from 1850 - 2017 (observations, for HadOST), with the contribution of various factors to this temperature trend (colored lines). The gray line is the sum of each of the depicted colored lines. The surface temperature trend takes into account changes in sea surface temperature measuring practices during the 1930s and 1940s, which I elaborate more on in "Myth: Karl et al. of the NOAA Misleadingly Altered Ocean Temperature Records to Increase Global Warming". The authors of this figure adapted it from the results of their 2019 paper. Note that this figure accounts for the long-term global surface temperature trend without recourse to large internal variability in the form of the Atlantic Multi-decadal Oscillation (AMO), as did figure 22. This supports the idea that the AMO played little role in driving long-term industrial-era global warming [16 - 18]. This figure displays global warming acceleration post-1998. Post-1998 acceleration also appears in global surface temperature trend analyses such as ERA5 (which is endorsed by the contrarians Judith Curry and Ryan Maue), NASA's GISTEMP, NOAA's global analysis, NCEP-2, and 20CR, consistent with other sources on accelerating climate change. For further discussion of accelerating warming, see section 2.1 of "Myth: The IPCC's 2007 ~0.2°C/decade Model-based Projection Failed and Judith Curry's Forecast was More Reliable". |
3. Posts Providing Further Information and Analysis
- "Myth: Karl et al. of the NOAA Misleadingly Altered Ocean Temperature Records to Increase Global Warming"
- Section 3.4 of "John Christy, Climate Models, and Long-term Tropospheric Warming"
- Section 2.10 of "Myth: Attributing Warming to CO2 Involves the Fallaciously Inferring Causation from a Mere Correlation"
- Section 3.4 of part 1 of "Christopher Monckton and Projecting Future Global Warming"
- Section 3.8 of part 2 of "John Christy and the Tropical Tropospheric Hot Spot"
- "Myth: Karl et al. of the NOAA Misleadingly Altered Ocean Temperature Records to Increase Global Warming"
- Section 3.4 of "John Christy, Climate Models, and Long-term Tropospheric Warming"
- Section 2.10 of "Myth: Attributing Warming to CO2 Involves the Fallaciously Inferring Causation from a Mere Correlation"
- Section 3.4 of part 1 of "Christopher Monckton and Projecting Future Global Warming"
- Section 3.8 of part 2 of "John Christy and the Tropical Tropospheric Hot Spot"
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