Page 20 - Climate Control Magazine September 2018

Natural Refrigerants
Paris Climate goals
may not be enough to stay below two degrees
MORE NEEDS TO BE DONE TO ENSURE THE PARIS CLIMATE AGREEMENT CAN DELIVER ON ITS PROMISE TO KEEP GLOBAL WARMING BELOW TWO DEGREES CELSIUS.
EVEN IF CARBON emission targets under the Paris Climate Agreement are met, there is still a serious risk of Earth entering what scientists call “Hothouse Earth” conditions.
A new study published by an international team of scientists in one of the world's most cited journals – Proceedings of the National Academy of Sciences (PNAS) – warns that keeping global warming to within 1.5 to 2 de- grees Celsius may be more difficult than pre- viously assessed. Put simply, more needs to be done.
A “Hothouse Earth” climate will in the long term stabilize at a global average of 4-5°C higher than pre-industrial tempera- tures with sea level 10-60 m higher than to- day, the study said.
Authors of the study, which was published last month, call for urgent action to accelerate the transition to an emission-free world economy.
"Human emissions of greenhouse gas are not the sole determinant of temperature on Earth. Our study suggests that human-in- duced global warming of 2°C may trigger other Earth system processes, often called “feed- backs”, that can drive further warming - even if we stop emitting greenhouse gases," accord- ing to the lead author Will Steffen from the Australian National University and Stockholm Resilience Centre.
Feedbacks referenced in the study include: loss of methane hydrates from the ocean floor, weakening land and ocean carbon sinks, in- creasing bacterial respiration in the oceans, Amazon rainforest dieback, loss of Arctic sum- mer sea ice, and reduction of Antarctic sea ice and polar ice sheets.
Currently, global average temperatures are just over 1°C above pre-industrial and rising at 0.17°C per decade. The authors of the study con-
Scientists are warning that existing targets could fail, more needs to be done.
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