---
title: "Soon and Baliunas controversy"
chunk: 2/6
source: "https://en.wikipedia.org/wiki/Soon_and_Baliunas_controversy"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T04:18:22.543337+00:00"
instance: "kb-cron"
---

== Publication ==
 Chris de Freitas, as an editor at Climate Research, accepted the paper written by Soon and Baliunas and it was published in the small refereed journal on 31 January 2003 under the title Proxy climatic and environmental changes of the past 1000 years. The article reviewed 240 previously published papers and tried to find evidence for temperature anomalies in the last thousand years such as the Medieval warm period (MWP) and the Little Ice Age (LIA). The authors pointed out their disagreement with the Mann, Bradley, and Hughes hockey stick studies; "Our results suggest a different interpretation of the multiproxy climates compared to recent conclusions of Mann et al. (1998, 1999, 2000)." Their abstract concluded that "Across the world, many records reveal that the 20th century is probably not the warmest or a uniquely extreme climatic period of the last millennium". The paper acknowledged funding support from the American Petroleum Institute, the Air Force Office of Scientific Research and NASA, while stating that the views were those of the authors and were independent of the sponsoring agencies.
In the Spring of 2003, Soon and Baliunas, with three additional co-authors, published a longer version of the paper in Energy and Environment. The three additional co-authors were Craig Idso, Sherwood Idso, and David Legates. A press release dated 31 March 2003 headed "20th Century Climate Not So Hot" announced the paper with a statement lacking the caveats of the original paper; "Soon and his colleagues concluded that the 20th century is neither the warmest century over the last 1000 years, nor is it the most extreme."
In the paper, Soon, Baliunas, and their co-authors investigated the correlation between solar variation and temperatures of the Earth's atmosphere. When there are more sunspots, the total solar output increases, and when there are fewer sunspots, it decreases. Soon and Baliunas attributed the Medieval warm period to such an increase in solar output, and believe that decreases in solar output led to the Little Ice Age, a period of cooling lasting until the mid-19th Century. In a statement to The Chronicle of Higher Education, Soon said that, "When you compare the 20th century to the previous nine centuries, you do not see the change in the 20th century as anything unusual or unprecedented."
Rather than showing quantitative data, they primarily categorized research by others into those supporting, and those not supporting, the MWP and the LIA as defined by themselves. Soon said "I was stating outright that I'm not able to give too many quantitative details, especially in terms of aggregating all the results". They used a very loose definition of climate anomaly, including any period of 50 years or more that was wet, dry, warm or cold. Though "mindful" that the MWP and LIA are both defined by temperature, "we emphasize that great bias would result if those thermal anomalies were to be dissociated" from climatic conditions such as wetness and dryness, but wetness and dryness were undefined and only "referred to the standard usage in English." Their selection of a 50-year plus period excluded recent warming, which had occurred in two periods of 30 years in the 20th century, with the greatest warming in the late 20th century.