Monday, July 17, 2017

+Myth: No Global Warming for Two Decades

The outline for this post is as follows:
  1. The Myth and Its Flaw
  2. Context and Analysis
  3. Posts Providing Further Information and Analysis
  4. References

This is the "+References" version of this post, which means that this post contains my full list of references and citations. If you would like an abbreviated and easier to read version, then please go to the "main 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 no warming for about two decades.

Purveyors of this myth include Christopher Monckton [1, pages 122 and 127; 2, pages 1379, 1385, and 1387], Willie Soon [1, pages 122 and 127; 2, pages 1379, 1385, and 1387], David Legates [1, pages 122 and 127; 2, pages 1379, 1385, and 1387], John Christy [3; 4], Ted Cruz [5, page 1], Anthony Watts [6], Patrick Michaels [7, page 5], and Paul (Chip) Knappenberger [7, page 5].

The myth's flaw: over the past two decades the ocean and land warmed [8 - 24], as has the lower atmosphere [3; 8; 25 - 28; 29, figure 3; 34]. This warming was reflected in the difference between the amount of energy Earth takes up vs. the amount of energy Earth release [30; 31; 32, figure 3].

2. Context and Analysis

Oceans and land warmed over the past two decades [8 - 24]. 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 [3; 8; 25 - 28; 29, figure 3; 34]. 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 [22; 30; 31; 32, figure 3]. 

The figures below illustrate some of this recent warming:

Figure 1: Comparison of ocean temperature records from 1997 to 2015 for different sources, relative to a 1997-2001 baseline. The sources are buoys, the NOAA's (National Ocean and Atmospheric Association) Extended Reconstructed Sea Surface Temperature (ERSST) record for both ERSSTv3b and the updated ERSSTv4, and the European Space Agency Climate Change Initiative (CCI) [13, figure 1].

Figure 2: Comparison of ocean temperature records from 1997 to 2015 for different sources. NOAA's Extended Reconstructed Sea Surface Temperature (ERSST) record for ERSSTv3b and ERSSTv4 are compared to ocean heat measurements from Argo floats. Argo(H2008), Argo(APDRC), and Argo(RG2000) represent three different near-surface temperature data-sets derived from the Argo data. ERSSTv4 data is presented relative to a 1997-2001 baseline, while the other data sources are aligned to the 2005-2007 baseline for ERSSTv4 [13, figure S2]. 

Figure 3: Global, annual, mean surface temperature relative to mean temperature during pre-industrial era (1720 - 1800), or relative to mean temperature from 1986 - 2005 in the case of ERA-Interim, as shown in multiple temperature analyses. Pre-2016 data came from a previous scientific publication [9], with later data added in a subsequent analysis [33].

Figure 4: Trend in global, monthly, mean surface temperature from 1979 to 2016 relative to baseline of 1981 - 2010, as shown in multiple temperature analyses. The solid green trend-line is represents the trend for 1998 - 2012, while the dotted black trend-line represents the trend for the full period from 1979 - 2016 [8].

Figure 5: Version 3.3 and version 4.0 of the Remote Sensing Systems (RSS) near-global lower tropospheric temperature analysis, along with version 5.6 and version 6.0 of the University of Alabama in Huntsville (UAH) near-global lower tropospheric temperature trends. RSS version 4.0 is an update of RSS version 3.3, while UAH version 6.0 is an update of UAH version 5.6. The lower lines (black, gray, red, and pink) indicate temperature relative to a baseline of 1979 - 1981. The upper lines (green and purple) display the difference between the relative temperature values. Quantified trends are from 1979 - 2016 [27].

Figure 6: Near global mid- to upper tropospheric temperature averaged for the UAH, NOAA, and RSS satellite-based analyses [25].

This warming cannot be accounted for in terms of an ocean cycle known as the El Niño Southern Oscillation, as I discuss in "Myth: El Niño Caused Most Post-1997 Warming". El Niño, however, does cause a more pronounced warming spike in 1998; this spike is greater in the troposphere than at Earth's surface (compare figure 3 to figures 5 and 6) due largely to a short term "tropospheric hot spot" that I discuss in "Myth: The Tropospheric Hot Spot is a Fingerprint of CO2-induced Warming".

3. Posts Providing Further Information and Analysis

4. References

  1. "Why models run hot: results from an irreducibly simple climate model"
  2. "Keeping it simple: the value of an irreducibly simple climate model"
  3. "Comparing tropospheric warming in climate models and satellite data"
  4. "Data or dogma? Promoting open inquiry in the debate over the magnitude of human impact on Earth’s climate. Archived webcast of hearing before the U.S. Senate Committee on Commerce, Science, and Transportation, Subcommittee on Space, Science, and Competitiveness, 8 December 2015"
  5. "A response to the “Data or Dogma?” hearing"
  7. "Lukewarming: The new climate science that changes everything"
  8. "A reassessment of temperature variations and trends from global reanalyses and monthly surface climatological datasets"
  9. "Estimating changes in global temperature since the pre-industrial period"
  10. "Global temperature evolution: recent trends and some pitfalls"
  11. "Coverage bias in the HadCRUT4 temperature series and its impact on recent temperature trends"
  12. Hansen et al.: "Global temperature in 2015"
  13. "Assessing recent warming using instrumentally homogeneous sea surface temperature records"
  14. "Unabated planetary warming and its ocean structure since 2006"
  15. "Tracking ocean heat uptake during the surface warming hiatus"
  16. "Assessing the impact of satellite-based observations in sea surface temperature trends"
  17. "A review of global ocean temperature observations: Implications for ocean heat content estimates and climate change"
  18. "Possible artifacts of data biases in the recent global surface warming hiatus"
  19. "Land surface temperature over global deserts: Means, variability, and trends"
  20. "On the definition and identifiability of the alleged “hiatus” in global warming"
  21. "Global land-surface air temperature change based on the new CMA GLSAT dataset"
  22. "Improved estimates of ocean heat content from 1960 to 2015"
  23. "Industrial-era global ocean heat uptake doubles in recent decades"
  24. "In situ–based reanalysis of the global ocean temperature and salinity with ISAS: Variability of the heat content and steric height"
  25. "Tropospheric warming over the past two decades"
  26. "Sensitivity of satellite-derived tropospheric temperature trends to the diurnal cycle adjustment"
  27. "A satellite-derived lower tropospheric atmospheric temperature dataset using an optimized adjustment for diurnal effects"
  28. "Atmospheric changes through 2012 as shown by iteratively homogenized radiosonde temperature and wind data (IUKv2)"
  29. "Internal variability in simulated and observed tropical tropospheric temperature trends"
  30. "Insights into Earth’s energy imbalance from multiple sources"
  31. Stephens and L'Ecuyer: "The Earth's energy balance"; doi: 10.1016/j.atmosres.2015.06.024
  32. "Reconciling estimates of ocean heating and Earth’s radiation budget"
  33. "Guest post: The challenge of defining the ‘pre-industrial’ era"
  34. "Troposphere-stratosphere temperature trends derived from satellite data compared with ensemble simulations from WACCM"