Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Lessons about a future warmer world using data from the past

26.06.2018

Selected intervals in the past that were as warm or warmer than today can help us understand what the Earth may be like under future global warming. A latest assessment of past warm periods, published in Nature Geoscience by an international team of 59 scientists from 17 nations, shows that in response to the warming ecosystems and climate zones will spatially shift and on millennial time scales ice sheets will substantially shrink.

The study was an outcome of a workshop that took place in Bern and was coordinated by the University of Bern in Switzerland, the University of New South Wales in Australia, and Oregon State University in the United States.


Gas bubbles and ash enclosed in the ice provide data about past climate and climate changes – such as a prehistoric vol-cano eruption 14.000 years ago.

Pete Bucktrout / British Antarctic Survey


Ice core drilling in Antarctica. Ice cores contain important cli-mate information, for example the atmospheric concentration of CO2.

Nerillie Abram

The compiled evidence from the past suggests that even with a global warming limited to within 2°C above preindustrial levels, as aimed at in the Paris Agreement, climate zones and ecosystems will shift, rapid polar warming may release additional greenhouse gases, and sea-level will rise by several meters over several thousand years. These observations show that many current climate models designed to project changes within this century may underestimate longer-term changes.

Over the past 3.5 million years, several time intervals are known for being 0.5-2°C warmer than the so-called preindustrial temperatures of the 19th century. These intervals reveal much stronger regional warming at high latitudes than in the tropics, similar to what models predict for a 2°C global warming by the year 2100. Although not all these past warmings were caused by higher CO2 concentrations, they are helpful to assess the regional effect of a warming of a scale comparable to that aimed at in the Paris Agreement.

Ecosystems and climate zones will shift

Ecosystems and climate zones will generally shift poleward or to higher altitudes. In response, permafrost thaw may release additional carbon dioxide and methane to the atmosphere, driving additional warming. Past observations suggest that if warming can be limited to no more than 2°C as proposed by the Paris accords, the risk of catastrophic runaway greenhouse gas feedbacks is relatively low. Nevertheless, the significant amount of additional CO2 released from permafrost and soils must be considered in future emission budgets.

“Accounting for the additional release of CO2 leaves even less room for error or delay as humanity seeks to lower its CO2 emissions and stabilize global climate within reasonable limits”, Hubertus Fischer, of the University of Bern, emphasizes.

Long-term sea-level rise of more than 6 meters

Even a warming of 1.5-2°C above preindustrial levels will be sufficient to trigger substantial long-term melting of ice in Greenland and Antarctica and sea-level rise of more than 6 meters that will last for thousands of years. Rates of sea-level rise higher than those of the last decades are likely.

Alan Mix of Oregon State University noted the importance of this sea-level rise, stating, “we are already beginning to see the effects of rising sea level. This rise may become unstoppable for millennia, impacting much of the world’s population, infrastructure, and economic activity that is located near the shoreline”.

Past warming stronger than predicted by climate models used for short-term forecasting
Comparison of observations of the past with computer simulations suggests that models may underestimate long-term warming and its amplification in polar regions.

Katrin Meissner of University of New South Wales, Australia, commented that, “while climate model projections seem to be trustworthy when considering relatively small changes over the next decades, it is worrisome that these models likely underestimate climate change under higher emission scenarios, such as a ‘business as usual’ scenario, and especially over longer time scales.”

According to the researchers, this information from the past underscores the urgency of reducing CO2 emissions soon to meet the Paris Agreements in this century and beyond.

PAGES and Warmer Worlds

The publication in Nature Geoscience is a result of the Past Global Changes (PAGES;
http://www.pastglobalchanges.org) integrated activity “Warmer Worlds” that uses paleoclimate evidence to assess a future warming. To this end the Warmer Worlds activity assembled about 50 renowned international researchers in April 2017 for a workshop in Bern, Switzerland funded by PAGES and the Oeschger Centre for Climate Change Research of the University of Bern. The publication is the outcome of this expert assessment. The Warmer Worlds activity is coordinated by Hubertus Fischer (University of Bern), Katrin Meissner (University of New South Wales, Sydney) and Alan Mix (Oregon State University, Corvallis, OR). PAGES, a network funded jointly by the US and Swiss National Science Foundations, is a core project of the global sustainability program Future Earth (http://www.futureearth.org) and has the goal to coordinate and promote past global change research.

Reference:
Fischer, H., Meissner, K.J., Mix, A.C., et al.: Palaeoclimate constraints on the impact of 2 °C anthropogenic warming and beyond. Nature Geoscience, 25 June 2018.
https://doi.org/ 10.1038/s41561-018-0146-0

For more information please contact:
Prof. Hubertus Fischer
Climate and Environmental Physics, Physics Institute & Oeschger Centre for Climate Change Research, University of Bern
Phone +41 31 631 85 03 (available per mail until 25 June) / hubertus.fischer@climate.unibe.ch

Associate Prof. Katrin Meissner
Climate Change Research Centre, University of New South Wales Sydney
Phone +61 9385 8962 / k.meissner@unsw.edu.au

Prof. Alan Mix
College of Earth, Ocean, and Atmospheric Sciences
Oregon State University, Corvallis, OR 97331-5503 USA
mix@coas.oregonstate.edu

Nathalie Matter | Universität Bern
Further information:
http://www.unibe.ch

More articles from Earth Sciences:

nachricht Volcanoes under pressure
18.11.2019 | Technical University of Munich (TUM)

nachricht New findings on the largest natural sulfur source in the atmosphere
18.11.2019 | Leibniz-Institut für Troposphärenforschung e. V.

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Machine learning microscope adapts lighting to improve diagnosis

Prototype microscope teaches itself the best illumination settings for diagnosing malaria

Engineers at Duke University have developed a microscope that adapts its lighting angles, colors and patterns while teaching itself the optimal...

Im Focus: Small particles, big effects: How graphene nanoparticles improve the resolution of microscopes

Conventional light microscopes cannot distinguish structures when they are separated by a distance smaller than, roughly, the wavelength of light. Superresolution microscopy, developed since the 1980s, lifts this limitation, using fluorescent moieties. Scientists at the Max Planck Institute for Polymer Research have now discovered that graphene nano-molecules can be used to improve this microscopy technique. These graphene nano-molecules offer a number of substantial advantages over the materials previously used, making superresolution microscopy even more versatile.

Microscopy is an important investigation method, in physics, biology, medicine, and many other sciences. However, it has one disadvantage: its resolution is...

Im Focus: Atoms don't like jumping rope

Nanooptical traps are a promising building block for quantum technologies. Austrian and German scientists have now removed an important obstacle to their practical use. They were able to show that a special form of mechanical vibration heats trapped particles in a very short time and knocks them out of the trap.

By controlling individual atoms, quantum properties can be investigated and made usable for technological applications. For about ten years, physicists have...

Im Focus: Images from NJIT's big bear solar observatory peel away layers of a stellar mystery

An international team of scientists, including three researchers from New Jersey Institute of Technology (NJIT), has shed new light on one of the central mysteries of solar physics: how energy from the Sun is transferred to the star's upper atmosphere, heating it to 1 million degrees Fahrenheit and higher in some regions, temperatures that are vastly hotter than the Sun's surface.

With new images from NJIT's Big Bear Solar Observatory (BBSO), the researchers have revealed in groundbreaking, granular detail what appears to be a likely...

Im Focus: New opportunities in additive manufacturing presented

Fraunhofer IFAM Dresden demonstrates manufacturing of copper components

The Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM in Dresden has succeeded in using Selective Electron Beam Melting (SEBM) to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

First International Conference on Agrophotovoltaics in August 2020

15.11.2019 | Event News

Laser Symposium on Electromobility in Aachen: trends for the mobility revolution

15.11.2019 | Event News

High entropy alloys for hot turbines and tireless metal-forming presses

05.11.2019 | Event News

 
Latest News

Scientists first to develop rapid cell division in marine sponges

21.11.2019 | Life Sciences

First detection of gamma-ray burst afterglow in very-high-energy gamma light

21.11.2019 | Physics and Astronomy

Research team discovers three supermassive black holes at the core of one galaxy

21.11.2019 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>