The Need For Precise Definitions In Climate Science – The Misuse Of The Terminology “Climate Change”

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My son had an insightful discussion on this subject in his post

The Narrow Defintion of Climate Change

where he refers to two of his papers

Pielke, Jr., R.A., 2005. Misdefining ‘‘climate change’’: consequences for science and action, Environmental Science & Policy, Vol. 8, pp. 548-561.

Pielke, Jr., R. A., 2004. What is Climate Change?, Issues in Science and Technology, Summer, 1-4.

*********ORIGINAL POST*************

The terminology in the field of climate and environmental science is filled with jargon words and the misuse of definitions. I have posted on this issue before with respect to the terms “global warming” and “climate change” in my posts

The Media (and Presidential Candidates) Remain In Error On The Distinction Between Global Warming And Climate Change


Recommended Definitions of “Global Warming” And “Climate Change”

To properly define these two terms, I recommended

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.

Today’s post is to further elaborate on the terms that are used.

With respect to the terminology “climate change“, this term is being extensively used to mean “anthropognic caused changes in climate” from nearly “static” climatic conditions; e.g. see the figure below [source of image]

This is why  terminology such as “climate stabilization” is misused; e. g. see

Climate Stabilization Targets: Emissions, Concentrations, and Impacts Over Decades to Millennia (2010)

where this National Academy report writes

This new report from the National Research Council concludes that emissions of carbon dioxide from the burning of fossil fuels have ushered in a new epoch where human activities will largely determine the evolution of Earth’s climate.

However, as documented in another Academy report

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

and summarized in the article

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.

the natural causes of climate variations and changes are important, as are the human influences. The human climate forcings 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.

As reported in the NRC (2005) report and written  in the Pielke et al 2009 article with respect to human climate forcings

In addition to greenhouse gas emissions, other first-order human climate forcings are important to understanding the future behavior of Earth’s climate. These forcings are spatially heterogeneous and include the effect of aerosols on clouds and associated precipitation [e.g., Rosenfeld et al., 2008], the infl uence of aerosol deposition (e.g., black carbon (soot) [Flanner et al. 2007] and reactive nitrogen [Galloway et al., 2004]), and the role of changes in land use/land cover [e.g., Takata et al., 2009]. Among their effects is their role in altering atmospheric and ocean circulation features away from what they would be in the natural climate system [NRC, 2005]. As with CO2, the lengths of time that they affect the climate are estimated to be on multidecadal time scales and longer.

With respect to natural climate forcings and feedbacks, in the article

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.

we wrote

The Earth’s climate system is highly nonlinear: inputs and outputs are not proportional, change is often episodic and abrupt, rather than slow and gradual, and multiple equilibria are the norm.

Thus, the assumption of a stable climate system, in the absence of human intervention, is a mischaracterization of the behavior of the real climate system.

“Climate change’ is, and always has been occuring. Humans are now adding to the complexity of forcings and feedbacks, but change has always been a part of the climate system.

Thus, rather than using terminolgy such as “climate change” [which has come to mean the human caused part mostly due to added greenhouse gases], I recommend just using the term “climate” or “climate system”. When change is discussed, the specific component that is being discussed should be presented, such as an increase in annual averaged surface air temperatures, a decrease in the length of growing season etc.  Phrases such as “changes in regional and global climate statistics” could be used.

There is a very important reason to scrap the use of “climate change” by the impacts community. Key societal and environental resources, such as water, food, energy, ecosystem function, and human health respond to climate not just to an incremental change in the climatic conditions.

Another misused term is “global change“, when really what is almost always meant is a local and/or regional change in the environmental conditions, including from climate. The  accurate terminology should be “environmental change“.

Thus, my recommendations are to replace terminology such as climate change, climate stabilization, climate distruption and global change with accurate terminology. With respect to impacts on key resources, climate is one of the stressors, not just the “change” part. When changes in climatic conditions are discussed, present the actual climate variable(s) that are being altered.

This issue of terminology has been important as we work to complete the 5 volume set of books for Elsevier titled

“Climate Vulnerability  – Understanding and Addressing Threats to Essential Resources”. 2013:  Eds  R.A. Pielke Sr., Faisal Hossain, Dev Niyogi, George Kallos, Jimmy Adegoke, Caradee Y. Wright, Timothy Seastedt, Katie Suding and Dallas Staley. Elsevier

which will appear early in 2013. Our edits for the chapters have required us to address the improper use of the terminology by some of the authors. The current weblog post is intended to alert others to the frequent mischaracterization of the climate system.

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