Global atmospheric CO2 levels hit record high

UN warns that drastic action is needed to meet climate targets set in the Paris agreement
Jonathan Watts and agencies The Guardian 30 Oct 17;

The concentration of carbon dioxide in the atmosphere increased at record speed last year to hit a level not seen for more than three million years, the UN has warned.

The new report has raised alarm among scientists and prompted calls for nations to consider more drastic emissions reductions at the upcoming climate negotiations in Bonn.

“Globally averaged concentrations of CO2 reached 403.3 parts per million (ppm) in 2016, up from 400.00 ppm in 2015 because of a combination of human activities and a strong El Niño event,” according to The Greenhouse Gas Bulletin, the UN weather agency’s annual flagship report.

This acceleration occurred despite a slowdown – and perhaps even a plateauing – of emissions because El Niño intensified droughts and weakened the ability of vegetation to absorb carbon dioxide. As the planet warms, El Niños are expected to become more frequent.

The increase of 3.3 ppm is considerably higher than both the 2.3 ppm rise of the previous 12 months and the average annual increase over the past decade of 2.08ppm. It is also well above the previous big El Niño year of 1998, when the rise was 2.7 ppm.

The study, which uses monitoring ships, aircraft and stations on the land to track emissions trends since 1750, said carbon dioxide in the atmosphere is now increasing 100 times faster than at the end of the last ice age due to population growth, intensive agriculture, deforestation and industrialisation.

The last time Earth experienced similar CO2 concentration rates was during the Pliocene era (three to five million years ago), when the sea level was up to 20m higher than now.

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The authors urged policymakers to step up countermeasures to reduce the risk of global warming exceeding the Paris climate target of between 1.5C and 2C.

“Without rapid cuts in CO2 and other greenhouse gas emissions, we will be heading for dangerous temperature increases by the end of this century, well above the target set by the Paris climate change agreement,” World Meteorological Organisation chief Petteri Taalas said in a statement.

The momentum from the Paris accord in 2015 is faltering due to the failure of national governments to live up to their promises. In a report to be released on Tuesday, UN Environment will show the gap between international goals and domestic commitments leaves the world on course for warming well beyond the 2C target and probably beyond 3C. International efforts to act have also been weakened by US president Donald Trump’s decision to quit the accord.

Prof Dave Reay, professor of carbon management at the University of Edinburgh, said: “This should set alarm bells ringing in the corridors of power. We know that, as climate change intensifies, the ability of the land and oceans to mop up our carbon emissions will weaken. There’s still time to steer these emissions down and so keep some control, but if we wait too long humankind will become a passenger on a one-way street to dangerous climate change.”

“The numbers don’t lie. We are still emitting far too much and this needs to be reversed,” the head of UN Environment Erik Solheim said in reaction to the new report. “What we need now is global political will and a new sense of urgency.”

The report comes amid growing concerns that nature’s ability to deal with CO2 is weakening. Recent studies show forest regions are being cleared and degraded so rapidly that they are now emitting more carbon than they absorb.

“These large increase show it is more important than ever to reduce our emissions to zero – and as soon as possible,” said Piers Forster, director of the Priestley International Centre for Climate at the University of Leeds. “If vegetation can no longer help out absorbing our emissions in these hot years we could be in trouble.”

The World Meteorological Organisation predicted 2017 will again break records for concentrations of carbon dioxide and methane, but the growth rate will not be as fast because there is no El Niño effect.


Record surge in atmospheric CO2 seen in 2016
Matt McGrath BBC 30 Oct 17;

Concentrations of CO2 in the Earth's atmosphere surged to a record high in 2016, according to the World Meteorological Organization (WMO).

Last year's increase was 50% higher than the average of the past 10 years.

Researchers say a combination of human activities and the El Niño weather phenomenon drove CO2 to a level not seen in 800,000 years.

Scientists say this risks making global temperature targets largely unattainable.

This year's greenhouse gas bulletin produced by the WMO is based on measurements taken in 51 countries. Research stations dotted around the globe measure concentrations of warming gases including carbon dioxide, methane and nitrous oxide.

The figures published by the WMO are what's left in the atmosphere after significant amounts are absorbed by the Earth's "sinks", which include the oceans and the biosphere.

2016 saw average concentrations of CO2 hit 403.3 parts per million, up from 400ppm in 2015.

"It is the largest increase we have ever seen in the 30 years we have had this network," Dr Oksana Tarasova, chief of WMO's global atmosphere watch programme, told BBC News.

"The largest increase was in the previous El Niño, in 1997-1998, and it was 2.7ppm; and now it is 3.3ppm. It is also 50% higher than the average of the last 10 years."

El Niño impacts the amount of carbon in the atmosphere by causing droughts that limit the uptake of CO2 by plants and trees.

Emissions from human sources have slowed down in the last couple of years according to research, but according to Dr Tarasova, it is the cumulative total in the atmosphere that really matters as CO2 stays aloft and active for centuries.

Over the past 70 years, says the report, the increase in CO2 in the atmosphere is nearly 100 times larger than it was at the end of the last ice age.

Rapidly increasing atmospheric levels of CO2 and other gases have the potential, according to the study, to "initiate unpredictable changes in the climate system... leading to severe ecological and economic disruptions".

The study notes that since 1990 there has been a 40% increase in total radiative forcing. That's the warming effect on our climate of all greenhouse gases.

"Geological-wise, it is like an injection of a huge amount of heat," said Dr Tarasova.

"The changes will not take 10,000 years, like they used to take before; they will happen fast. We don't have the knowledge of the system in this state; that is a bit worrisome!"

According to experts, the last time the Earth experienced a comparable concentration of CO2 was three to five million years ago, in the mid-Pliocene Epoch. The climate then was 2-3C warmer, and sea levels were 10-20m higher due to the melting of Greenland and the West Antarctic ice sheets.

Other experts in the field of atmospheric research agreed that the WMO findings were a cause for concern.

"The 3ppm CO2 growth rate in 2015 and 2016 is extreme - double the growth rate in the 1990-2000 decade," Prof Euan Nisbet from Royal Holloway University of London, UK, told BBC News.

"It is urgent that we follow the Paris agreement and switch rapidly away from fossil fuels. There are signs this is beginning to happen, but so far the air is not yet recording the change."

Another concern in the report is the continuing, mysterious rise of methane levels in the atmosphere, which were also larger than the average over the past 10 years. Prof Nisbet says there is a fear of a vicious cycle, where methane drives up temperatures which in turn releases more methane from natural sources.

"The rapid increase in methane since 2007, especially in 2014, 2015, and 2016, is different. This was not expected in the Paris agreement. Methane growth is strongest in the tropics and sub-tropics. The carbon isotopes in the methane show that growth is not being driven by fossil fuels. We do not understand why methane is rising. It may be a climate change feedback. It is very worrying."

The implications of these new atmospheric measurements for the targets agreed under the Paris climate pact are quite negative, say observers.

"The numbers don't lie. We are still emitting far too much and this needs to be reversed," said Erik Solheim, head of UN Environment.

"We have many of the solutions already to address this challenge. What we need now is global political will and a new sense of urgency."

The report has been issued just a week ahead of the next instalment of UN climate talks, in Bonn. Despite the declaration by President Trump that he intends to take the US out of the deal, negotiators meeting in Germany will be aiming to advance and clarify the rulebook of the Paris agreement.

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