The last time levels were this high was three to five million years ago
Last year saw a record-breaking surge in carbon dioxide (CO2) levels in the earth’s atmosphere, increasing 50 per cent higher than the last ten-year average, according to a report by the World Meteorological Organization (WMO).
Researchers say that this increase has pushed atmospheric CO2 to levels not seen for 800,000 years, and the last time the earth experienced similar levels was three to five million years ago, which back then caused global average temperatures to be two to three degrees warmer than today, with sea-levels about 20 metres higher due to the melting of the Greenland and Antarctic ice sheets.
Speaking to BBC News, chief of WMO’s global atmosphere watch programme, Dr. Oksana Tarasova, said “Geological-wise, it is like an injection of a huge amount of heat… 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!”
Although CO2 emissions from human activity have slowed down over recent years, Dr Tarasova says that it is the cumulative effect of CO2 that is problematic, as once releases into the atmosphere it can stay aloft and active for centuries.
Further to this, the WMO report says that such a rapid surge in CO2 levels can “initiate unpredictable changes in the climate system… leading to severe ecological and economic disruptions”. Scientists also warn that the global temperature targets set out by the Paris climate change agreement are largely unattainable.
The historic agreement, approved by 195 countries in 2015, has suffered a major setback this year after US President Donald Trump announced in June this year that the US will pull out of the agreement by 2020. This is of particular concern as the USA is the world’s second-largest emitter of CO2 levels, with China coming out on top.
On top of this, UN Environment released a report on 31st October which highlighted the gap between the goals of the Paris agreement and each countries’ actual commitments could lead to the global average temperature to exceed three degrees celcius, well above the two degrees maximum target.
Speaking to the Guardian, 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 report also predicts that 2017 will be another record-breaking year for levels of methane in the atmosphere. Although researchers say this methane is not from human activity, it is nevertheless a powerful greenhouse gas and the causes for its increase are still unknown.
Speaking to BBC News, Prof Euan Nisbet from the Royal Holloway University of London said: “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…We do not understand why methane is rising. It may be a climate change feedback. It is very worrying.”
The WMO report has been releases a week ahead of UN climate talks in Bonn, Germany, where negotiators aim to advance and clarify the targets set out by the Paris agreement.