---
title: "Soon and Baliunas controversy"
chunk: 1/6
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"
---

The Soon and Baliunas controversy involved the publication in 2003 of a review study titled Proxy climatic and environmental changes of the past 1000 years, written by aerospace engineer Willie Soon and astronomer Sallie Baliunas and published in the journal Climate Research. In the review, the authors expressed disagreement with the hockey stick graph and argued that historical temperature changes were related to solar variation rather than greenhouse gas emissions as was the position of the Intergovernmental Panel on Climate Change and other researchers. The publication was quickly taken up by the George W. Bush administration as a basis for amending the first Environmental Protection Agency's Report on the Environment.
The paper was strongly criticized by numerous scientists for its methodology and for its misuse of data from previously published studies, which prompted concerns about the peer review process of the paper. The controversy resulted in the resignation of half of the editors of the journal and in the admission by its publisher, Otto Kinne, that the paper should not have been published as it was. The article and responses to it featured in further global warming controversy, including questions about funding of the paper.

== Background ==

=== IPCC and the Kyoto protocol ===

By the late 1980s, scientific findings indicated that greenhouse gases including CO2 emissions were leading to global warming. There was increasing public and political interest, and in 1987 the World Meteorological Organization pressed for an international scientific panel to assess the topic. The United States Reagan administration, worried about political influence of scientists, successfully lobbied for the 1988 formation of the Intergovernmental Panel on Climate Change to provide reports subject to detailed approval by government delegates. The IPCC First Assessment Report included a "schematic diagram" of global temperature variations over the last thousand years which has been traced to a graph based loosely on Hubert Lamb's 1965 paper.  The IPCC Second Assessment Report (SAR) of 1996 featured a graph of an early northern hemisphere reconstruction by Raymond S. Bradley and Phil Jones, and noted the 1994 reconstruction by Hughes and Henry F. Diaz questioning how widespread the Medieval Warm Period had been at any one time.
Efforts to reduce CO2 emissions were resisted by industrial interests, and political pressures increased as the international Kyoto Protocol was opposed by lobbyists such as the American Petroleum Institute who sought climatologists to dissent and undermine its scientific credibility.
In 1998, Mann, Bradley and Hughes published a multiproxy study (MBH98) which used a new statistical approach to find patterns of climate change in both time and global distribution, over the past six centuries In 1999 they extended their approach to 1,000 years in a study (MBH99) summarised in a graph which showed relatively little change until a sharp rise in the 20th century, earning it the nickname of the hockey stick graph. In 2001 the IPCC Third Assessment Report (TAR) included a version of this graph which was frequently featured in literature publicising the findings of the IPCC report that the 1990s were likely to have been the warmest decade, and 1998 the warmest year, of the past millennium in the Northern Hemisphere.

=== Soon and Baliunas ===
After the publicity the MBH99 study had been given by the IPCC Third Assessment Report (TAR), the "hockey stick controversy" developed in which the graph was targeted by those opposing ratification of the Kyoto Protocol on global warming, including Willie Soon and Sallie Baliunas. Both were astrophysicists at the Harvard-Smithsonian Center for Astrophysics: Soon had for a long time said that climate change was primarily due to solar variation, while Baliunas had previously been noted for disputing that man-made chemicals (halocarbon refrigerants such as CFCs) were causing ozone depletion. They prepared a literature review which used data from previous papers to argue that the Medieval Warm Period had been warmer than the 20th century, and that recent warming was not unusual. They sent their paper to one of the editors of Climate Research, Chris de Freitas, an opponent of action to curb carbon dioxide emissions who has been characterized by Fred Pearce as a "climate contrarian". Unusually for a peer reviewed journal, Climate Research at the time did not have one editor in chief that would distribute submitted papers amongst its editors, leaving its authors free to "shop around" for one that would be friendly to their views.