History of Climate Change Science Timeline

(1820 – Present)

The history of climate change science traces humanity's understanding of Earth's climate system, beginning with early discoveries about greenhouse gases in the 1800s, through pivotal 20th-century research linking carbon dioxide emissions to warming, and culminating in today's international scientific assessments and climate policy. More Less

Go to: Timeline | Event List | Key Facts | Directory

Early Discoveries

Joseph Fourier proposes greenhouse effect concept

1824

French mathematician Joseph Fourier reasoned that the atmosphere traps heat like a glass vessel warmed by the sun, laying the conceptual groundwork for what would later be called the greenhouse effect. His insight explained why Earth's surface is warmer than calculations of solar radiation alone would predict.

Image source: Joseph Fourier

Eunice Foote links carbon dioxide to warming

1856

American scientist Eunice Newton Foote conducted experiments showing that air enriched with carbon dioxide absorbed more solar heat than ordinary air. She suggested that an atmosphere of CO2 would give Earth a higher temperature, one of the earliest experimental demonstrations linking the gas to warming.

Image source: Eunice Newton Foote

John Tyndall measures infrared absorption by gases

1859

Irish physicist John Tyndall used precise laboratory apparatus to measure the infrared-absorbing properties of gases, demonstrating that water vapor and carbon dioxide strongly absorb radiant heat. His work provided rigorous physical evidence for the atmospheric greenhouse mechanism.

Image source: John Tyndall

Svante Arrhenius calculates CO2 warming effect

1896

Swedish chemist Svante Arrhenius performed laborious hand calculations estimating how changes in atmospheric carbon dioxide would affect global temperature. He predicted that doubling CO2 would warm the planet by several degrees, producing the first quantitative estimate of climate sensitivity.

Image source: Svante Arrhenius

Svante Arrhenius calculates CO2 warming effect

Guy Stewart Callendar links fossil fuels to warming

1938

British engineer Guy Stewart Callendar compiled temperature records from around the world and showed that global temperatures had risen over the preceding half century. He attributed this trend to rising carbon dioxide from fossil fuel combustion, a hypothesis later known as the Callendar effect.

Image source: Guy Stewart Callendar

Guy Stewart Callendar links fossil fuels to warming

Revelle and Suess show oceans absorb CO2 slowly

1957

Roger Revelle and Hans Suess demonstrated that chemical buffering in seawater limits how quickly the oceans can absorb excess carbon dioxide. Their 'great experiment' paper warned that most human-emitted CO2 would remain in the atmosphere, setting the stage for systematic monitoring.

Image source: Roger Revelle

Keeling begins continuous CO2 measurements at Mauna Loa

Mar 1958

Charles David Keeling established continuous measurements of atmospheric carbon dioxide at the Mauna Loa Observatory in Hawaii. The resulting Keeling Curve revealed a steady rise in CO2 concentrations overlaid with seasonal cycles, becoming the iconic record of human influence on the atmosphere.

Image source: Keeling Curve

Policy and Public Awareness

US President's Science Advisory Committee warns on CO2

1965

A report by the US President's Science Advisory Committee explicitly warned that rising carbon dioxide emissions could modify global climate, marking one of the first high-level government acknowledgments of anthropogenic climate change as a serious policy concern.

Study warns of human impact on global environment

1970

The MIT-sponsored Study of Critical Environmental Problems brought together scientists who warned about carbon dioxide buildup and other pollutants altering climate. It helped bring atmospheric science concerns into the emerging environmental movement.

Image source: MIT Press

Hansen testifies before US Congress on global warming

Jun 23, 1988

NASA scientist James Hansen testified to the US Senate that global warming had begun and was attributable to human activities. Delivered during a summer heat wave, his testimony brought climate change into mainstream public discourse and political debate.

Image source: James Hansen

Earth Summit adopts UN Framework Convention on Climate Change

Jun 1992

At the Rio de Janeiro Earth Summit, nations adopted the UNFCCC, committing signatories to prevent dangerous anthropogenic interference with the climate system. The treaty created the framework for subsequent international climate negotiations.

Image source: United Nations Framework Convention on Climate Change

Kyoto Protocol adopted to cut greenhouse gas emissions

Dec 11, 1997

Negotiators meeting in Kyoto, Japan agreed on binding emission reduction targets for developed countries under the UNFCCC. The Kyoto Protocol entered into force in 2005 and represented the first legally binding international commitment to limit greenhouse gases.

Image source: Kyoto Protocol

Climatic Research Unit email controversy erupts

Nov 2009

Hackers released emails from the University of East Anglia's Climatic Research Unit weeks before the Copenhagen summit. Multiple subsequent investigations cleared scientists of misconduct, but the episode fueled public skepticism and media debates over climate science.

Copenhagen climate summit ends without binding deal

Dec 2009

World leaders met in Copenhagen hoping to negotiate a successor to the Kyoto Protocol but produced only a non-binding political accord. The summit highlighted the political difficulties of translating scientific urgency into global action.

Image source: 2009 United Nations Climate Change Conference

Paris Agreement sets global warming targets

Dec 12, 2015

Nearly 200 nations adopted the Paris Agreement, pledging to hold global warming well below 2 degrees Celsius above preindustrial levels and pursue efforts to limit it to 1.5 degrees. The accord shifted to nationally determined pledges rather than binding quotas.

Image source: Paris Agreement

Paris Agreement sets global warming targets

20th Century Advances

Manabe and Wetherald publish first credible climate model

1967

Syukuro Manabe and Richard Wetherald developed a one-dimensional radiative-convective model that realistically represented the atmosphere's response to increased carbon dioxide. Their work estimated a warming of about 2 degrees Celsius for doubled CO2 and pioneered modern computer climate modeling.

Image source: Syukuro Manabe

Vostok ice core reveals ancient CO2-temperature link

1985 - 1998

Analysis of deep ice cores from Vostok Station in Antarctica revealed atmospheric CO2 concentrations over hundreds of thousands of years, showing a tight correlation between greenhouse gases and Antarctic temperatures across glacial-interglacial cycles.

Image source: Ice core

Mann publishes hockey stick temperature reconstruction

1998

Michael Mann and colleagues published a reconstruction of Northern Hemisphere temperatures over the past millennium, showing relative stability until a sharp twentieth-century rise. The 'hockey stick' graph became a powerful visual symbol of recent unprecedented warming.

Image source: Hockey stick graph

Paleoclimate record extends through EPICA Dome C core

2004 - 2008

European scientists drilled and analyzed the EPICA Dome C ice core in Antarctica, extending the record of atmospheric composition back 800,000 years. It confirmed that current CO2 levels far exceed any natural levels in that span.

Image source: Epica (band)

Arctic sea ice hits dramatic record low

Sep 2007

Satellite observations recorded a startling minimum in Arctic sea ice extent, shattering previous records decades ahead of many model projections. The event underscored the rapid pace of polar climate change and amplified public attention worldwide.

Image source: Arctic sea ice decline

Global Carbon Project tracks emissions record highs

2011

The Global Carbon Project reported that annual carbon dioxide emissions from fossil fuels surpassed record thresholds despite economic turbulence, quantifying the persistent growth of the principal driver of anthropogenic warming.

Image source: Global Carbon Project

International Assessments

Charney report affirms confidence in warming projections

1979

The US National Research Council's Charney Report concluded that there was no reason to doubt that doubling atmospheric CO2 would lead to roughly 3 degrees Celsius of warming. Its estimate of climate sensitivity has remained remarkably stable for decades.

Image source: Charney Report

First World Climate Conference held in Geneva

Feb 1979

Scientists and policymakers gathered in Geneva for the first World Climate Conference, organized under the auspices of the World Meteorological Organization. The conference called for international cooperation in studying climate change and its impacts.

Intergovernmental Panel on Climate Change established

1988

The World Meteorological Organization and the United Nations Environment Programme jointly created the IPCC to assess the scientific literature on climate change. The panel became the authoritative international body for summarizing climate science for governments.

Image source: Intergovernmental Panel on Climate Change

IPCC publishes First Assessment Report

1990

The IPCC's first comprehensive assessment confirmed that human-caused emissions were substantially increasing atmospheric greenhouse gas concentrations and would likely enhance the greenhouse effect. Its findings directly informed negotiations toward a global climate treaty.

IPCC Second Assessment Report strengthens attribution claim

1995

The IPCC's second assessment famously concluded that the balance of evidence suggested a discernible human influence on global climate. This statement marked a turning point in scientific consensus on detection and attribution of anthropogenic warming.

Image source: IPCC Second Assessment Report

IPCC Fourth Assessment Report declares warming unequivocal

2007

The IPCC's fourth assessment stated that warming of the climate system is unequivocal and very likely caused by human activities. The work, shared with Al Gore, earned the 2007 Nobel Peace Prize and solidified the scientific consensus globally.

IPCC Fifth Assessment Report refines sensitivity estimates

2013 - 2014

The fifth IPCC assessment concluded that human influence on the climate system is clear and raised confidence in projections, while narrowing the likely range of equilibrium climate sensitivity. It also introduced cumulative carbon budgets framing future mitigation goals.

Image source: IPCC Fifth Assessment Report

IPCC Special Report on 1.5 degrees issued

Oct 2018

The IPCC warned that limiting warming to 1.5 degrees Celsius required rapid, transformative reductions in emissions within decades, highlighting sharply greater risks at 2 degrees. The report galvanized movements demanding stronger climate action worldwide.

Sixth IPCC Assessment Report confirms human-driven warming

Aug 2021

The IPCC's sixth assessment declared it unequivocal that human influence has warmed the atmosphere, ocean, and land, with recent decades warmer than any comparable period in at least 2,000 years. The report emphasized that every increment of warming brings escalating risks.

Key Facts

In the 1820s, Joseph Fourier proposed that Earth's atmosphere traps heat like a glass box, laying the foundation for greenhouse effect theory.
In 1859, John Tyndall experimentally demonstrated that gases such as carbon dioxide and water vapor absorb infrared radiation, confirming the greenhouse effect mechanism.
In 1896, Svante Arrhenius calculated that doubling atmospheric CO2 could raise global temperatures by several degrees, producing the first quantitative estimate of human-caused warming.
In 1958, Charles Keeling began continuous measurements of atmospheric CO2 at Mauna Loa Observatory, creating the famous 'Keeling Curve' showing steadily rising concentrations.
Established in 1988, the Intergovernmental Panel on Climate Change (IPCC) has since become the leading international authority assessing climate science, winning the Nobel Peace Prize in 2007.

Source

This History of Climate Change Science timeline was generated with the help of AI, using information found on the internet.

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