Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

High CO2 levels cause warming in the tropics

30.06.2014

The impact of the greenhouse gas CO2 on the Earth's temperature is well established by climate models and temperature records over the past 100 years, as well as coupled records of carbon dioxide concentration and temperature throughout Earth history.

However, past temperature records have suggested that warming is largely confined to mid-to-high latitudes, especially the poles, whereas tropical temperatures appear to be relatively stable: the tropical thermostat model.

The new results, published today in Nature Geoscience, contradict those previous studies and indicate that tropical sea surface temperatures were warmer during the early-to-mid Pliocene, an interval spanning about 5 to 3 million years ago.

The Pliocene is of particular interest because CO2 concentrations then were thought to have been about 400 parts per million, the highest level of the past 5 million years but a level that was reached for the first time last summer due to human activity. The higher CO2 levels of the Pliocene have long been associated with a warmer world, but evidence from tropical regions suggested relatively stable temperatures.

Project leader and Director of the Cabot Institute, Professor Richard Pancost said: "These results confirm what climate models have long predicted – that although greenhouse gases cause greater warming at the poles they also cause warming in the tropics. Such findings indicate that few places on Earth will be immune to global warming and that the tropics will likely experience associated climate impacts, such as increased tropical storm intensity."

The scientists focussed their attention on the South China Sea which is at the fringe of a vast warm body of water, the West Pacific Warm Pool (WPWP). Some of the most useful temperature proxies are insensitive to temperature change in the heart of the WPWP, which is already at the maximum temperature they can record. By focussing on the South China Sea, the researchers were able to use a combination of geochemical records to reconstruct sea surface temperature in the past.

Not all of the records agree, however, and the researchers argue that certain tools used for reconstructing past ocean temperatures should be re-evaluated.

The paper's first author, Charlotte O'Brien added: "It's challenging to reconstruct the temperatures of the ocean many millions of years ago, and each of the tools we use has its own set of limitations. That is why we have used a combination of approaches in this investigation. We have shown that two different approaches agree – but a third approach agrees only if we make some assumptions about how the magnesium and calcium content of seawater has changed over the past 5 million years. That is an assumption that now needs to be tested."

The work was funded by the UK's Natural Environment Research Council and is ongoing.

Dr Gavin Foster at the University of Southampton is particularly interested in coupling the temperature records with improved estimates of Pliocene carbon dioxide levels. He said: "Just as we continue to challenge our temperature reconstructions we must challenge the corresponding carbon dioxide estimates. Together, they will help us truly understand the natural sensitivity of the Earth system and provide a better framework for predicting future climate change."

Hannah Johnson | Eurek Alert!
Further information:
http://www.bristol.ac.uk

Further reports about: CO2 China Geoscience Institute Pacific activity greenhouse interest temperature tropics

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>