As a follow up to my testimony to Congress
Oral Presentation On March 8 2011 At The House of Representatives Energy and Commerce Committee Hearing Climate Science and EPA’s Greenhouse Gas Regulation [My written testimony is available from http://republicans.energycommerce.house.gov/Media/file/Hearings/Energy/030811/Pielke.pdf],
I answered the following questions in response to a request from Congressman Morgan Griffith
Answers to questions posed by The Honorable Morgan Griffith regarding the hearing “Climate Science and EPA’s Greenhouse Gas Regulations”
By Roger A. Pielke Sr.
Q:Do we know what the temperatures were during the period in history known as the Great Optimum which lead to the rise of Mesopotamian and Egyptian cultures? That was a time in history of global warming, but how warm did it get?
A:It is regional climate, not a global average surface temperature that matters in terms of cultures. We live in regions and it is the local and regional weather and climate that we experience that matters. For the Mesopotamian and Egyptian cultures, unfortunately, we do not have quantitative measures (e.g. temperatures and rainfall statistics) to determine what the details of the climate were at this time period. We do know with respect to Roman culture, that in North Africa (such as in Tunisia and Egypt) there were woodlands on the hills (which are no longer there), large areas of wheat cultivation (which helped finance the Roman Republic and Empire), and even animals such as lions which are no longer found in this area. These examples of ancient cultures do show us that climate is always changing and that it is the regional climate that matters.
Q: How about for the period known as the Lesser Optimum? And how much did the temperature rise then? We know this period led to Vikings dominating Europe.
A:The same issues as #1 occur. We just do not have good enough data to diagnose what were the temperatures and precipitation during this time period. We do know, however, based on archeological records that Viking settlement of Greenland occurred during a regionally warm period, which was followed by regional cooling that resulted in the loss of that colony. This shows that regional climate variations are a natural part of the climate system. While, in my view, there is no doubt humans are altering the regional climate of many locations (irrespective of any global average surface temperature trend). However, the IPCC models have not shown any skill at predicting multi-decadal changes in the regional climate due to either human- and natural climate forcings and feedbacks.
Q:Has the IPCC studies why ice caps on Mars are melting? Do we know whether this is a shift in the orbit of Mars? Or is the Sun putting out more radiant heat?
A:Mars does have ice caps (both of liquid water and carbon dioxide) which change over time. This occurs both due to seasonal effects as well as the orbital path of Mars with respect to its distance from the Sun. The orbit itself has not shifted. In terms of output of solar energy, we have much more rigorous ways to monitor solar output (e. g. SORCE – “Solar and Anthropogenic Influences on Earth: The Current Solar Minimum and Predictions for Future Decades” http://lasp.colorado.edu/sorce/news/sns/2010/sns_jun_2010.pdf).
Q: Why was I taught in school 40 years ago that greenhouse gases were going to lead to a new ice age?
A:We know that the addition of greenhouse gases is always a positive (warming) radiative climate forcing. There is no disagreement on this in the scientific community. With respect to the IPCC viewpoint, it is the addition of CO2 and other human inputs of greenhouse gases that cause initial warming that is amplified by the feedback of added greenhouse gas warming from water vapor as the oceans warm.
What the IPCC has inadequately communicated is that if the ocean surface does not warm (e.g. due to other water cycle feedbacks such as clouds and precipitation; due to radiative cooling from aerosols; or natural climate feedbacks such as from atmospheric/ocean circulation changes), there is no water vapor feedback. The CO2 radiative forcing by itself is relatively small. The water cycle is poorly modeled, however, as shown in Stephens, G. L., T. L’Ecuyer, R. Forbes, A. Gettlemen, J.‐C. Golaz, A. Bodas‐Salcedo, K. Suzuki, P. Gabriel, and J. Haynes (2010), Dreary state of precipitation in global models, J. Geophys. Res., 115, D24211, doi:10.1029/2010JD014532, so that, despite what the IPCC claims, they cannot yet properly predict how the water vapor responds to human and natural climate forcings.
Q:In regard to radiant heat and sunspot effects, how could this affect temperatures?
A:The Sun’s total output does change but only slightly over time since satellite records commenced. Most of the variations are in its shortest wavelengths (ultraviolet, X-ray). If the Sun’s output was significantly reduced or increased, there would be an effect of the global average heat content. The best source of this information is the SORCE project that I listed above.
For recent papers on this subject, I recommend Lean, J. L., and D. H. Rind (2009): How Will Earth’s Surface Temperature Change in Future Decades?, Geophys. Res. Lett., doi:10.1029/2009GL038932 and Scafetta N., R. C. Willson (2009), ACRIM-gap and TSI trend issue resolved using a surface magnetic flux TSI proxy model, Geophys. Res. Lett., 36, L05701, doi:10.1029/2008GL036307.
There is a set of guest posts on my weblog on this subject (e.g. see https://pielkeclimatesci.wordpress.com/2009/08/03/nicola-scafetta-comments-on-solar-trends-and-global-warming-by-benestad-and-schmidt/ and https://pielkeclimatesci.wordpress.com/2009/08/17/guest-weblog-solar-variability-and-its-effect-on-climate-change-by-nicola-scafetta/).
Q: What is the optimum temperature for man?
A:There is no optimum temperature. First, human society has developed over a wide range of climates. Second, there is no single temperature that we experience; we typically have maximum temperature during the day and minimum temperatures at night. Winters are colder than summers. It is also important to emphasize that a global average surface temperature or its trend over time is irrelevant for the temperatures that society and the environment deal with. It is the regional and local climate that matters.
Q:Is there an ideal average temperature that we need to return to, and if so what is it? What do we know from history about the fluctuations in temperature and their impact on mankind?
A:The answer to #6 addresses this. There is no ideal temperature. We also know that regional temperatures (and precipitation) vary within ranges between seasons, between years and decades, and over longer time periods. The multi-decadal climate models, such as reported by the IPCC, have not shown any skill at predicting these variations for yearly and longer time scales for the 20th century. We, therefore, should have no confidence in their skill for the 21st century including the extent that humans are altering the climate system. A recent paper of mine –
Pielke Sr., R.A., 2010: Comment on ” A Unified Modeling Approach to Climate System Prediction”, Bull. Amer. Meteor. Soc., 91, 1699–1701, DOI:10.1175/2010BAMS2975 https://pielkeclimatesci.files.wordpress.com/2011/03/r-360.pdf
discusses this issue.
As to how to move forward, I recommend a new approach as recommended in my weblog post
A Way Forward In Climate Science Based On A Bottom-Up Resource-Based Perspective. https://pielkeclimatesci.wordpress.com/2010/08/03/a-way-forward-in-climate-science-based-on-a-bottom-up-resourse-based-perspective/
and in a newly submitted paper
Pielke Sr., R.A., R. Wilby, D. Niyogi, F. Hossain, K. Dairuku, J. Adegoke, G. Kallos, T. Seastedt, and K. Suding, 2011: Dealing with complexity and extreme events using a bottom-up, resource-based vulnerability perspective. AGU Monograph on Complexity and Extreme Events in Geosciences, submitted. https://pielkeclimatesci.files.wordpress.com/2011/03/r-365.pdf.
We recommend
“There are 5 broad areas that we can use to define the need for vulnerability assessments: water, food, energy, human health and ecosystem function. Each area has societally critical resources. The vulnerability concept requires the determination of the major threats to these resources from climate, but also from other social and environmental issues. After these threats are identified for each resource, then the relative risk from natural- and human-caused climate change (estimated from the GCM projections, but also the historical, paleo-record and worst case sequences of events) can be compared with other risks in order to adopt the optimal mitigation/adaptation strategy.”
This is a distinctly different approach than used by the IPCC (and CCSP) assessment process, and I would be glad to discuss further with you if you would like.
Climate Science: Roger Pielke Sr. 