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- Predictions of substantial global warming assume high climate sensitivity to a doubling of carbon dioxide emissions in the atmosphere.
- For decades, scientists have debated the effect of climate sensitivity, due to the uncertain nature of climate feedback in various models.
- Estimates in peer reviewed studies range from 0.8°C warming to almost 6.0°C warming by 2100.
- Such a large range of uncertainty means climate model temperature projections remain dubious, at best.
- The best evidence indicates climate sensitivity is at the low end of the range, unlikely to exceed 1.5°C in the 21st century.
Declaring future predictions of global warming “settled science” requires a fairly precise calculation of future temperatures. However, since climate sensitivity was first identified more than 40 years ago, scientists and climate models have produced a very broad range of potential future temperature patterns. Calculations for a doubling of atmospheric carbon dioxide range from 0.8°C warming to 6.0°C future warming by 2100.
If climate scientists don’t understand the Earth’s atmosphere well enough to nail down a true climate sensitivity estimate for increased carbon dioxide, how can we trust climate model projections of future warming that rely on such an uncertain value? Climate sensitivity estimates from real-world atmospheric data suggest (see here and here) man-made global warming this century is unlikely to exceed 1.5°C total and its climatic effects might actually be beneficial for humans and the environment.
- Explained: Climate Sensitivity. MIT news. http://news.mit.edu/2010/explained-climate-sensitivity
- Ad Hoc Study Group on Carbon Dioxide and Climate (1979). Carbon Dioxide and Climate: A Scientific Assessment. National Academy of Sciences. doi:10.17226/12181. ISBN 978-0-309-11910-8. https://web.archive.org/web/20110813231807/http://www.atmos.ucla.edu/~brianpm/download/charney_report.pdf
- Earth’s Climate Sensitivity: Apparent Inconsistencies in Recent Assessments. Schwartz et al, 7 November 2014, Earth’s Future. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2014EF000273
- On the Observational Determination of Climate Sensitivity and Its Implications Richard S. Lindzen and Yong-Sang Choi Asia-Pacific J. Atmos. Sci., 47(4), 377-390, 2011 DOI:10.1007/s13143-011-0023-x http://www-eaps.mit.edu/faculty/lindzen/236-Lindzen-Choi-2011.pdf
- On the Misdiagnosis of Surface Temperature Feedbacks from Variations in Earth’s Radiant Energy Balance Remote Sens. 2011, 3, 1603-1613; doi:10.3390/rs3081603 http://www.drroyspencer.com/wp-content/uploads/Spencer_Misdiagnos_11.pdf
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