permaculture

[Lawrence London <lfljvenaura@gmail.com>]

Nature Geoscience
https://www.nature.com/ngeo/
Collection: Carbon budgets
Budgets of carbon emissions that are consistent with limiting warming to no
more than 1.5 °C over preindustrial…
Collection: Carbon budgets <https://www.nature.com/collections/fgmlwncmxd>

https://www.nature.com/collections/fgmlwncmxd
Budgets of carbon emissions that are consistent with limiting warming to no
more than 1.5 °C over preindustrial temperatures have been hotly debated,
following the Paris Agreement on climate change targets. Here we present
comments and primary research discussing the impacts of the debate on
decision making processes, and the issues that the climate science
community now needs to grapple with.


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Current Issue | July 2018
Volume 11 Issue 7

Global warming could be far worse than predicted, new study suggests

Collapsing polar ice caps, a green Sahara Desert, a 20-foot sea-level rise.

That's the potential future of Earth, a new study
<https://www.nature.com/articles/s41561-018-0146-0> suggests, noting that
global warming could be twice as warm as current climate models predict.

The rate of warming is also remarkable: “The changes we see today are much
faster than anything encountered in Earth’s history. In terms of rate of
change, we are in uncharted waters,” said study co-author Katrin Meissner
<http://web.science.unsw.edu.au/%7Ekatrinmeissner/> of the University of
New South Wales in Australia.

This could mean the landmark Paris Climate Agreement – which seeks to
limit global warming to 2 degrees Celsius (3.6 degrees Fahrenheit) above
pre-industrial levels – may not be enough to ward off catastrophe.

“Even with just 2 degrees of warming – and potentially just 1.5 degrees –
significant impacts on the Earth system are profound,” said study
co-author Alan
Mix <http://ceoas.oregonstate.edu/profile/mix/>, a scientist from Oregon
State University.

“We can expect that sea-level rise could become unstoppable for millennia,
impacting much of the world’s population, infrastructure and economic
activity,” Mix said.

In looking at Earth's past, scientists can predict what the future will
look like. In the study, the researchers looked back at natural global
warming periods over the past 3.5 million years and compared them
to current man-made warming.

By combining a wide range of measurements from ice cores, sediment layers,
fossil records, dating using atomic isotopes and many other established
paleoclimate methods, the researchers pieced together the impact of those
climatic changes.

Human-inflicted climate change is caused by the burning of fossil fuels
such as coal, oil and gas, which release heat-trapping greenhouse gases
such as carbon dioxide and methane into the the atmosphere.

Study lead author Hubertus Fischer
<http://www.oeschger.unibe.ch/about_us/people/profiles/hubertus_fischer/index_eng.html>
of the University of Bern in Switzerland and his team found that our
current climate predictions may underestimate long-term warming by as much
as a factor of two.

Meissner said that "climate models appear to be trustworthy for small
changes, such as for low-emission scenarios over short periods, say over
the next few decades out to 2100. But as the change gets larger or more
persistent ... it appears they underestimate climate change."

The research also revealed how large areas of the polar ice caps could
collapse and significant changes to ecosystems could see the Sahara Desert
become green and the edges of tropical forests turn into fire-dominated
savanna.

However, Meissner said "we cannot comment on how far in the future these
changes will occur."

Referring to the study findings, lead author Fischer said that without
serious reduction in carbon dioxide emissions, there is "very little margin
for error to meet the Paris targets.”

The study, which was conducted by dozens of researchers from 17
countries, was published last week in Nature Geoscience
<https://www.nature.com/ngeo/>, a peer-reviewed British journal.