Subscribe to our free daily newsletters
. 24/7 Space News .




Subscribe to our free daily newsletters



CLIMATE SCIENCE
Climate risk classification created to account for potential 'existential' threats
by Staff Writers
San Diego CA (SPX) Sep 19, 2017


Researchers projected warming scenarios that vary based on what societal actions are taken to reduce emissions. Image courtesy Scripps Institution of Oceanography at UC San Diego.

A new study evaluating models of future climate scenarios has led to the creation of the new risk categories "catastrophic" and "unknown" to characterize the range of threats posed by rapid global warming. Researchers propose that unknown risks imply existential threats to the survival of humanity.

These categories describe two low-probability but statistically significant scenarios that could play out by century's end, in a new study by Veerabhadran Ramanathan, a distinguished professor of climate and atmospheric sciences at Scripps Institution of Oceanography at the University of California San Diego, and his former Scripps graduate student Yangyang Xu, now an assistant professor at Texas A and M University.

The risk assessment stems from the objective stated in the 2015 Paris Agreement regarding climate change that society keep average global temperatures "well below" a 2C (3.6F) increase from what they were before the Industrial Revolution.

Even if that objective is met, a global temperature increase of 1.5C (2.7F) is still categorized as "dangerous," meaning it could create substantial damage to human and natural systems. A temperature increase greater than 3C (5.4F) could lead to what the researchers term "catastrophic" effects, and an increase greater than 5C (9F) could lead to "unknown" consequences which they describe as beyond catastrophic including potentially existential threats. The specter of existential threats is raised to reflect the grave risks to human health and species extinction from warming beyond 5C, which has not been experienced for at least the past 20 million years.

The scientists term warming probability of five percent or less as a "low-probability high-impact" scenario and assess such scenarios in the analysis "Well Below 2C: Mitigation strategies for avoiding dangerous to catastrophic climate changes," which will appear in the journal Proceedings of the National Academy of Sciences on Sept. 14.

Ramanathan and Xu also describe three strategies for preventing the gravest threats from taking place.

"When we say five percent-probability high-impact event, people may dismiss it as small but it is equivalent to a one-in-20 chance the plane you are about to board will crash," said Ramanathan. "We would never get on that plane with a one-in-20 chance of it coming down but we are willing to send our children and grandchildren on that plane."

The researchers defined the risk categories based on guidelines established by the Intergovernmental Panel on Climate Change (IPCC) and previous independent studies. "Dangerous" global warming includes consequences such as increased risk of extreme weather and climate events ranging from more intense heat waves, hurricanes, and floods, to prolonged droughts. Planetary warming between 3C and 5C could trigger what scientists term "tipping points" such as the collapse of the West Antarctic Ice Sheet and subsequent global sea-level rise, and the dieback of the Amazon rainforest.

In human systems, catastrophic climate change is marked by deadly heat waves becoming commonplace, exposing over 7 billion people to heat related mortalities and famine becoming widespread. Furthermore, the changes will be too rapid for most to adapt to, particularly the less affluent, said Ramanathan.

Risk assessments of global temperature rise greater than 5C have not been undertaken by the IPCC. Ramanathan and Xu named this category "unknown??" with the question marks acknowledging the "subjective nature of our deduction." The existential threats could include species extinctions and major threats to human water and food supplies in addition to the health risks posed by exposing over 7 billion people worldwide to deadly heat.

With these scenarios in mind, the researchers identified what measures can be taken to slow the rate of global warming to avoid the worst consequences, particularly the low-probability high-impact events. Aggressive measures to curtail the use of fossil fuels and emissions of so-called short-lived climate pollutants such as soot, methane and HFCs would need to be accompanied by active efforts to extract CO2 from the air and sequester it before it can be emitted. It would take all three efforts to meet the Paris Agreement goal to which countries agreed at a landmark United Nations climate conference in Nov 2015.

Xu and Ramanathan point out that the goal is attainable. Global CO2 emissions had grown at a rate of 2.9 percent per year between 2000 and 2011, but had slowed to a near-zero growth rate by 2015. They credited drops in CO2 emissions from the United States and China as the primary drivers of the trend. Increases in production of renewable energy, especially wind and solar power, have also bent the curve of emissions trends downward. Other studies have estimated that there was by 2015 enough renewable energy capacity to meet nearly 24 percent of global electricity demand.

Short-lived climate pollutants are so called because even though they warm the planet more efficiently than carbon dioxide, they only remain in the atmosphere for a period of weeks to roughly a decade whereas carbon dioxide molecules remain in the atmosphere for a century or more. The authors also note that most of the technologies needed to drastically curb emissions of short-lived climate pollutants already exist and are in use in much of the developed world. They range from cleaner diesel engines to methane-capture infrastructure.

"While these are encouraging signs, aggressive policies will still be required to achieve carbon neutrality and climate stability," the authors wrote.

The release of the study coincides with the start of Climate Week NYC in New York, a summit of business and government leaders to highlight global climate action. Ramanathan and colleagues will deliver a complementary report detailing the "three-lever" mitigation strategy of emissions control and carbon sequestration on Sept. 18 at the United Nations.

That report was produced by the Committee to Prevent Extreme Climate Change, chaired by Ramanathan, Nobel Prize winner Mario Molina of UC San Diego, and Durwood Zaelke, who leads an advocacy organization, the Institute for Governance and Sustainable Development, with 30 experts from around the world including China and India.

CLIMATE SCIENCE
Is the Earth warming? The ocean gives you the answer
Beijing, China (SPX) Sep 15, 2017
Humans have released carbon dioxide and other greenhouse gases, and the result is an accumulation of heat in the Earth's climate system, commonly referred to as "global warming". "How fast is the Earth's warming?" is a key question for decision makers, scientists and general public. Previously, the global mean surface temperature has been widely used as a key metric of global warming. Howe ... read more

Related Links
University of California - San Diego
Climate Science News - Modeling, Mitigation Adaptation


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

CLIMATE SCIENCE
Voyager Spacecraft: 40 Years of Solar System Discoveries

Trump names former Navy aviator to head NASA

What's hot and what's not at Berlin's IFA tech fair

'Star Trek' actor Shatner sends message to Voyager

CLIMATE SCIENCE
Rocket fever launches UB students to engineering competition in New Mexico

SLS Core Stage Simulator Will Pave Way for Mission Success

NASA Concludes Summer of Testing with Fifth Flight Controller Hot Fire

ISRO suspects pyro elements failed to separate rocket's heat shield

CLIMATE SCIENCE
Discovery of boron on Mars adds to evidence for habitability

Life on Mars: Let's Try Oman Desert First for Space Mission

Citizen scientists spot Martian 'spiders' in unexpected places

Big dishes band together

CLIMATE SCIENCE
China, Russia to Have Smooth Space Cooperation, Says Expert

Kuaizhou-11 to send six satellites into space

Russia, China May Sign 5-Year Agreement on Joint Space Exploration

ESA and Chinese astronauts train together

CLIMATE SCIENCE
Bids for government funding prove strong interest in LaunchUK

Blue Sky Network Reaffirms Commitment to Brazilian Market

India to Launch Exclusive Satellite for Afghanistan

Lockheed Martin invests $350M in state-of-the-art satellite production facility

CLIMATE SCIENCE
Physicists predict nonmetallic half-metallicity

New microscopy method for quick and reliable 3-D imaging of curvilinear nanostructures

HZDR physicists discover optimum conditions for laser plasma acceleration

Chinese video site offers virtual escape from 'boring' reality

CLIMATE SCIENCE
Could interstellar ice provide the answer to birth of DNA

Climate change for aliens

X-Rays Reveal Temperament of Possible Planet-Hosting Stars

Earth as Hybrid Planet: The Anthropocene Era in Astrobiological Context

CLIMATE SCIENCE
Pluto features given first official names

Jupiter's Auroras Present a Powerful Mystery

New Horizons Files Flight Plan for 2019 Flyby

Juno Scientists Prepare for Seventh Science Pass of Jupiter




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement