* 1.5C limit allows for no new emitting infrastructure-scientists
* Without negative emission, CCS technology, limit in jeopardy
* Existing infrastructure lifetimes would have to be reduced
By Nina Chestney
LONDON, July 1 (Reuters) - Carbon emissions from existing and planned fossil fuel energy plants and projects will exceed the amount needed to curb global warming, jeopardising a 1.5 degree Celsius temperature limit goal, scientists said in a study on Monday.
In 2015, almost 200 countries agreed a radical shift away from fossil fuels with a goal of limiting a rise in average global temperatures to well below 2 degrees Celsius (3.6 Fahrenheit) above pre-industrial times while "pursuing efforts" for a safer threshold of 1.5C.
But economic development and industrialisation around the world has resulted in an expansion of fossil fuel infrastructure, such as power plants and pipelines. The world is currently on track for at least a 3C rise.
The paper published in the journal Nature by scientists from U.S. and Chinese universities used data from existing and planned fossil fuel energy infrastructure as of the end of 2018 to estimate future carbon dioxide (CO2) emissions.
They found that future emissions from that infrastructure, such as power plants and pipelines, are larger than the amount that can be emitted under a 1.5C limit.
"Our estimates suggest that little or no additional CO2-emitting infrastructure can be commissioned and that infrastructure retirements that are earlier than historical ones (or retrofits with carbon capture and storage technology) may be necessary, in order to meet the Paris Agreement climate goals," the paper said.
Infrastructure lifetimes would need to be reduced to less than 25 years and capacity factors to less than 30%, for example.
Without such changes, the goals of the global climate pact, the Paris Agreement, are in jeopardy, the study said.
Last year, a U.N.-backed panel of scientists said manmade CO2 emissions would have to reach "net zero" by mid-century to contain warming at 1.5C.
The amount of electricity from renewables would need to surge and decrease from coal and gas, using technology to capture carbon and store it underground.
As of the end of 2018, 579 gigawatts (GW) of coal-fired generation capacity, 583 of gas- and 40 GW of oil-fired generation capacity is proposed to be built over the next several years, the Nature study said.
If the existing fossil fuel infrastructure around the world continues to operate as it has in the past, it will emit around 658 gigatonnes (Gt) of CO2, the study added.
More than half of these emissions are projected to come from the electricity sector. Infrastructure in China, the United States and the European Union represents around 41%, 9% and 7% of those emissions, respectively.
If built, power plants which are planned, permitted or under construction globally would emit an additional 188 Gt of CO2.
"Committed emissions from existing and proposed energy infrastructure (about 846 Gt CO2) thus represent more than the entire remaining carbon budget if warming is to be limited to 1.5C, with a probability of 50–66% (420–580 Gt CO2)," the scientists said.
The authors of the Nature paper are from the Tsinghua University in China, the University of California, Carnegie Institution for Science and Global Energy Monitor in the United States.
(Reporting by Nina Chestney. Editing by Jane Merriman)
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