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.
The greenhouse effect
What happens to incoming solar radiation?
6% is scattered by the atmosphere, 20% is absorbed by the atmosphere and clouds, 20% is reflected by clouds, 49% is absorbed by the Earth's surface and 5% is reflected by the Earth's surface.
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.
Thomas Chamberlin
Thomas Chamberlin created a model of the global carbon cycle. The model included 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.
Harald Sverdrup
Harald Sverdrup (pictured behind the white dog) explored the Arctic Ocean with Roald Amundsen.
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.
Oceanographer Dave Keeling
Dave Keeling accurately measured CO2 in the atmosphere on Mauna Loa in Hawaii and detected an annual rise. In 1960, CO2 in the atmosphere was 315ppm (parts per million) and the mean global temperature was 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.
First global temperature measurements via satellite
The Nimbus-3 satellite provided the first global temperature measurements beginning in 1969.
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.
Argo float
Argo floats only spend a short time at the surface, while they send data to a satellite. They then sink to 1,500 m and drift with the current.
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.
National Science Challenges logo
The National Science Challenges were collaborative and multi-disciplinary research programmes. The Challenges were launched between 2014 and 2016, and ended in mid-2024.
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.
October 2020 – NIWA deploys more than 100 Argo floats
A pandemic did not prevent NIWA scientists from deploying more than 100 floats in 2020, but it did prevent them from leaving the RV Kaharoa. NIWA has deployed more than 1,100 Argo floats in the Pacific, Indian and Southern Ocean over 22 voyages since 2004.
July 2024 – Warming ocean and coastal waters
Stats NZ reports between 2022 and 2023, oceanic and coastal waters around Aotearoa New Zealand reached their warmest annual temperatures since the series began in 1982.
Related content
Antarctica tipping points looks at the irreversible changes we could be facing if we fail to keep global warming below 2℃.
Our interactive planning pathways and teacher PLD on climate change resources provide excellent support for teachers wanting to use the wicked problem of climate change to promote science learning in their classroom.
Learn more about the impacts of climate change by exploring the climate change topic.
Useful links
The websites below, provide up-to-date figures and interactives related to climate change:
