The ocean, CO₂ and climate change – timeline

A look at the history of some aspects of ocean studies, including the interaction of the ocean with climate and atmospheric carbon dioxide.

1859 – Greenhouse effect

John Tyndall identifies water vapour and CO₂ as gases in the atmosphere that could trap heat rays.

1896 – Prediction of global warming

Swedish scientists Svante Arrhenius and Arvid Högbom realise oceans take up CO₂. First prediction of global warming due to CO₂ in the atmosphere from industrial emissions. Many scientists disagree.

1897– Carbon cycle model

Thomas Chamberlin creates model of global carbon cycle. The model includes long-term changes in CO₂ in oceans and atmosphere.

1906 – Oceans and climate

Thomas Chamberlin realises that ocean temperature and salinity help control climate. He notes that warm oceans give up CO₂, cool ones take it up.

1908 – CO₂ and acidification

John Gregory realises that an increase in CO₂ will mean an increase in carbonic acid in the oceans.

1938 – CO₂ and temperature (again)

Guy Callender argues that CO₂ levels are rising and causing an increase in global temperature. This revives earlier interest in the topic, but many scientists disagree.

1942 – Deep ocean currents

Harald Sverdrup describes how cold, dense water could sink and cause deep ocean currents, but there is no way of measuring this at the time.

1948 – Carbon cycle can cope

George Hutchinson states that the carbon cycle regulates itself and can cope with increased carbon from the burning of fossil fuels.

1957 – Oceans and CO₂

Roger Revelle and Hans Suess work out that the oceans are not taking up enough CO₂ to make up for the increased amounts being pumped into the atmosphere by humans.

1960 – Rising CO₂ measured

Dave Keeling accurately measures CO₂ in the atmosphere on Mauna Loa in Hawaii and detects an annual rise. In this year, CO₂ in the atmosphere is 315ppm (parts per million) and the mean global temperature is 13.9°C.

1967 – A new warning

Syukuro Manabe and Richard Wetherald warn again that increasing CO₂ in the atmosphere due to human activities will raise global temperatures due to greenhouse effect.

1969 – First satellite measurements

Nimbus-3 satellite starts to provide global temperature measurements.

1978 – Better remote sensing

Nimbus-7 satellite launched, providing global sea surface temperatures and colour. The colour is related to the amount of phytoplankton growing in the sea.

1981 – Warmest year on record

Strong global warming since the 1970s is reported, with 1981 the warmest year on record.

1985 – Not just CO₂

Veerabhadran Ramanathan and others announce that other gases, not just CO₂, have a role in the greenhouse effect.

1985 – Villach conference

A conference at Villach, in Austria, marks the start of a rapid acceptance of the idea that humans do play a large part in climate change.

1992 – Drifting ocean floats

Russ Davis and Doug Webb develop pop-up drifter floats to measure ocean currents.

1992 – Sea level satellite

TOPEX/Poseidon satellite starts to very accurately measure global sea levels. Changes in sea level reflect changes in temperature, as water expands when warmed and contracts when cool.

1999 – Global remote sensing

NASA’s Terra satellite is launched to collect data monitoring many aspects of Earth’s environment and climate systems.

2000 – First Argo floats

First Argo floats launched to measure currents, temperature and salinity. There are over 3,000 floats by 2010, continuously drifting around the oceans and sending back data via satellites.

2009 – CO₂ reaches new high

CO₂ in atmosphere reaches 385ppm, with a mean global temperature of 14.4°C – the warmest for hundreds, perhaps thousands, of years. Compare these figures to those recorded in 1960.

2010 – Aquarius satellite

In May, the Aquarius satellite is launched to make the first sea surface salinity measurements from space.

2014 – The Deep South – Te Kōmata o Te Tonga

The Deep South National Science Challenge, hosted by NIWA, sets out to understand the role of the Antarctic and the Southern Ocean in determining our climate and our future environment.

2016 – Hottest year on record

Measurements from NASA and the National Oceanic and Atmospheric Administration put the Earth on track to surpass 2015 as the hottest year on record.

2017 onwards – increase in protests

News of disasters, such as tropical cyclones and wildfires, and intensified scientific warnings lead to increasing public concern, especially among younger people. This spurs public demonstrations and civil disobedience, such as school Strikes for climate change.

May 2020 – record temperatures

The mean global temperature is 14.8°C, the warmest in tens of thousands of years. The level of CO₂ in the atmosphere is 415 ppm, the highest in millions of years.