For the next two weeks, I am on travel and will not be posting. In this post, I want to summarize some of my viewpoints on climate science.
i) There has been global warming over the last several decades. The ocean is the component of the climate system that is best suited for quantifying climate system heat change. The warming has been less than predicted by the multi-decadal global model predictions; e.g.
Pielke Sr., R.A., 2008: A broader view of the role of humans in the climate system. Physics Today, 61, Vol. 11, 54-55.
R. S. Knox, David H. Douglass 2010: Recent energy balance of Earth International Journal of Geosciences, 2010, vol. 1, no. 3 (November) â€“ In press doi:10.4236/ijg2010.00000
Levitus, S., et al. (2012), World ocean heat content and thermosteric sea level change (0-2000), 1955-2010, Geophys. Res. Lett.,doi:10.1029/2012GL051106.
ii) The use of a global annual average surface temperature is an inadequate metric to quantify global warming and cooling. The documentation of the poor siting quality over land is one reason it is such a poor metric. For examples of papers and weblog posts that document this issue, see
Pielke Sr., R.A., 2003: Heat storage within the Earth system. Bull. Amer. Meteor. Soc., 84, 331-335.
Pielke Sr., R.A., C. Davey, D. Niyogi, S. Fall, J. Steinweg-Woods, K. Hubbard, X. Lin, M. Cai, Y.-K. Lim, H. Li, J. Nielsen-Gammon, K. Gallo, R. Hale, R. Mahmood, S. Foster, R.T. McNider, and P. Blanken, 2007: Unresolved issues with the assessment of multi-decadal global land surface temperature trends. J. Geophys. Res., 112, D24S08, doi:10.1029/2006JD008229.
Fall, S., A. Watts, J. Nielsen-Gammon, E. Jones, D. Niyogi, J. Christy, and R.A. Pielke Sr., 2011: Analysis of the impacts of station exposure on the U.S. Historical Climatology Network temperatures and temperature trends. J. Geophys. Res., 116, D14120, doi:10.1029/2010JD015146.Copyright (2011) American Geophysical Union.
McNider, R.T., G.J. Steeneveld, B. Holtslag, R. Pielke Sr, S. Mackaro, A. Pour Biazar, J.T. Walters, U.S. Nair, and J.R. Christy, 2012: Response and sensitivity of the nocturnal boundary layer over land to added longwave radiative forcing. J. Geophys. Res., doi:10.1029/2012JD017578.
iii) The involvement of citizen scientists to document the siting quality is a very significant achievement; e.g. see
Roger Tattersall’s Surface Stations Survey
Watts Up With That http://www.surfacestations.org/
iv) The human addition to CO2 into the atmosphere is a first-order climate forcing. It is the largest annual-global averaged positive human radiative forcing.
IPCC: Climate change 2007: the physical science basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). 2007.
v) However, global warming is not equivalent to climate change. Significant, societally important climate change, due to both natural- and human- climate forcings, could occur even without global warming or cooling.
I propose these definitions be adopted in our statement
“Global Warming” is an increase in the global annual average heat content measured in Joules.
“Climate Change” is any multi-decadal or longer alteration in one or more physical, chemical and/or biological components of the climate system.
vi) The correct summary statement on climate, in my view, is that
Natural causes of climate variations and changes are important. In addition, the human influences are significant and involve a diverse range of first-order climate forcings, including, but not limited to, the human input of carbon dioxide (CO2). Most, if not all, of these human influences on regional and global climate will continue to be of concern during the coming decades.
In addition to greenhouse gas emissions, these other first-order human climate forcings that are important to understanding the future behavior of Earth’s climate are spatially heterogeneous and include the effect of aerosols on clouds and associated precipitation, the influence of aerosol deposition (e.g., black carbon (soot), and reactive nitrogen), and the role of changes in land use/land cover. Among their effects is their role in altering atmospheric and ocean circulation features away from what they would be in the natural climate system. As with CO2, the lengths of time that they affect the climate are estimated to be on multidecadal time scales and longer.
Examples of reports and papers that document this more scientifically robust perspective include
Kabat, P., Claussen, M., Dirmeyer, P.A., J.H.C. Gash, L. Bravo de Guenni, M. Meybeck, R.A. Pielke Sr., C.J. Vorosmarty, R.W.A. Hutjes, and S. Lutkemeier, Editors, 2004: Vegetation, water, humans and the climate: A new perspective on an interactive system. Springer, Berlin, Global Change - The IGBP Series, 566 pp.
National Research Council, 2005: Radiative forcing of climate change: Expanding the concept and addressing uncertainties. Committee on Radiative Forcing Effects on Climate Change, Climate Research Committee, Board on Atmospheric Sciences and Climate, Division on Earth and Life Studies, The National Academies Press, Washington, D.C., 208 pp.
"Inadvertent Weather Modification" An Information Statement of the American Meteorological Society (Adopted by the AMS Council on 2 November 2010).
Pielke Sr., R.A., A. Pitman, D. Niyogi, R. Mahmood, C. McAlpine, F. Hossain, K. Goldewijk, U. Nair, R. Betts, S. Fall, M. Reichstein, P. Kabat, and N. de Noblet-Ducoudré, 2011: Land use/land cover changes and limate: Modeling analysis and observational evidence. WIREs Clim Change 2011, 2:828.850. doi: 10.1002/wcc.144.
Avila, F. B., A. J. Pitman, M. G. Donat, L. V. Alexander, and G. Abramowitz (2012), Climate model simulated changes in temperature extremes due to land cover change, J. Geophys. Res., 117, D04108, doi:10.1029/2011JD016382
Pielke Sr., R., K. Beven, G. Brasseur, J. Calvert, M. Chahine, R. Dickerson, D. Entekhabi, E. Foufoula-Georgiou, H. Gupta, V. Gupta, W. Krajewski, E. Philip Krider, W. K.M. Lau, J. McDonnell, W. Rossow, J. Schaake, J. Smith, S. Sorooshian, and E. Wood, 2009: Climate change: The need to consider human forcings besides greenhouse gases. Eos, Vol. 90, No. 45, 10 November 2009, 413. Copyright (2009) American Geophysical Union.
McAlpine, C.A., W.F. Laurance, J.G. Ryan, L. Seabrook, J.I. Syktus, A.E. Etter, P.M. Fearnside, P. Dargusch, and R.A. Pielke Sr. 2010: More than CO2: A broader picture for managing climate change and variability to avoid ecosystem collapse. Current Opinion in Environmental Sustainability, 2:334-336, DOI10.1016/j.cosust.2010.10.001.
vii) Natural variations and longer term change have been significantly underestimated. Also, climate prediction is an initial-value problem.
Pielke, R.A., 1998: Climate prediction as an initial value problem. Bull. Amer. Meteor. Soc., 79, 2743-2746.
Rial, J., R.A. Pielke Sr., M. Beniston, M. Claussen, J. Canadell, P. Cox, H. Held, N. de Noblet-Ducoudre, R. Prinn, J. Reynolds, and J.D. Salas, 2004: Nonlinearities, feedbacks and critical thresholds within the Earth's climate system. Climatic Change, 65, 11-38.
"The Climate Is Not What You Expect" by S. Lovejoy and D. Schertzer 2012 [submitted to BAMS]
vi) Attempts to significantly influence impacts from regional and local-scale climate based on controlling CO2 emissions alone is an inadequate policy for this purpose. With respect to CO2 [and for all other human climate forcings], the emphasis should be on supporting technological developments to mitigate these threats; e.g. see
The Climate Fix, 2010: R. Pielke Jr. Basic Books http://theclimatefix.com/
vii) Policymakers should look for win-win policies in order to improve the environment. The costs and benefits of the regulation of the emissions of CO2 into the atmosphere need to be evaluated together with all other possible environmental regulations. The goal should be to seek politically and technologically practical ways to reduce the vulnerability of the environment and society to the entire spectrum of human-caused and natural risks including those from climate.
Pielke, R. A., Sr., R. Wilby, D. Niyogi, F. Hossain, K. Dairuku,J. Adegoke, G. Kallos, T. Seastedt, and K. Suding (2012), Dealing with complexity and extreme events using a bottom-up, resource-based vulnerability perspective, in Extreme Events and Natural Hazards: The Complexity Perspective, Geophys. Monogr. Ser., vol. 196, edited by A. S. Sharma et al. 345–359, AGU, Washington, D. C., doi:10.1029/2011GM001086. [the article can also be obtained from here]
viii) Global and regional climate models have not demonstrated skill at predicting multi-decadal changes in climate statistics on regional and local climate in hindcast studies; e.g. see
Pielke Sr., R.A., and R.L. Wilby, 2012: Regional climate downscaling – what’s the point? Eos Forum, 93, No. 5, 52-53, doi:10.1029/2012EO050008.
Examples of the substantial inadequacies of the climate models to provide skillful multi-decadal predictions are presented in the peer-reviewed papers reported on in these posts
What we recommend in our Pielke et al (2012) paper in terms of an approach to mitigation and adaptation is, as written in its abstract,
“We discuss the adoption of a bottom-up, resource-based vulnerability approach in evaluating the effect of climate and other environmental and societal threats to societally critical resources. This vulnerability concept requires the determination of the major threats to local and regional water, food, energy, human health, and ecosystem function resources from extreme events including climate, but also from other social and environmental issues. After these threats are identified for each resource, then the relative risks can be compared with other risks in order to adopt optimal preferred mitigation/adaptation strategies.
This is a more inclusive way of assessing risks, including from climate variability and climate change than using the outcome vulnerability approach adopted by the IPCC. A contextual vulnerability assessment, using the bottom-up, resource-based framework is a more inclusive approach for policymakers to adopt effective mitigation and adaptation methodologies to deal with the complexity of the spectrum of social and environmental extreme events that will occur in the coming decades, as the range of threats are assessed, beyond just the focus on CO2 and a few other greenhouse gases as emphasized in the IPCC assessments.”
When I return, I look forward to assessing further the above issues, and also invite readers on my weblog to submit guest posts to appear after I am back, which refute any of the above conclusions.