Yeah, every single scientist.
www.nas.org
Consensus of experts
The United States' foremost scientific agencies and organizations have recognized global warming as a human-caused problem that should be addressed. The
U.S. Global Change Research Program has published a series of scientific reports documenting the causes and impacts of global climate change.
NOAA,
NASA, the
National Science Foundation, the
National Research Council, and the
Environmental Protection Agency have all published reports and fact sheets stating that Earth is warming mainly due to the increase in human-produced heat-trapping gases.
On their
climate home page, the National Academies of Sciences, Engineering, and Medicines says, "Scientists have known for some time, from multiple lines of evidence, that humans are changing Earth’s climate, primarily through greenhouse gas emissions," and that "Climate change is increasingly affecting people’s lives."
The American Meteorological Society (AMS) issued
this position statement: "Scientific evidence indicates that the leading cause of climate change in the most recent half century is the anthropogenic increase in the concentration of atmospheric greenhouse gases, including carbon dioxide (CO2), chlorofluorocarbons, methane, tropospheric ozone, and nitrous oxide." (Adopted April 15, 2019)
The American Geophysical Union (AGU) issued
this position statement: "Human-induced climate change requires urgent action. Humanity is the major influence on the global climate observed over the last 50 years. Rapid societal responses can significantly lessen negative outcomes." (Reaffirmed in November 2019)
The American Association for the Advancement of Science (AAAS)
What We Know site states: "Based on the evidence, about 97 percent of climate scientists agree that human-caused climate change is happening."
Consensus of evidence
These scientific organizations have not issued statements in a void; they echo the findings of individual papers published in refereed scientific journals. The Institute for Scientific Information (ISI) maintains a database of over 8,500 peer-reviewed science journals, and multiple studies of this database show evidence of overwhelming agreement among climate scientists. In 2004, science historian Naomi Oreskes published the results of her examination of the ISI database in the journal
Science. She reviewed 928 abstracts published between 1993 and 2003 related to human activities warming the Earth's surface, and stated, "Remarkably, none of the papers disagreed with the consensus position."
This finding hasn't changed with time. In 2016, a review paper summarized the results of several independent studies on peer-reviewed research related to climate. The authors found results consistent with a 97-percent consensus that human activity is causing climate change.
Probably the most definitive assessments of global climate science come from the Intergovernmental Panel on Climate Change (IPCC). Founded by the United Nations in 1988, the IPCC releases periodic reports, and each major release includes three volumes: one on the science, one on impacts, and one on mitigation. Each volume is authored by a separate team of experts, who reviews, evaluates, and summarizes relevant research published since the prior report. Each IPCC report undergoes several iterations of expert and government review. The 2007 IPCC report, for instance, received some 90,000 comments, and each comment received an individual response.
