In the week where climate talks are being held in Bonn, and we still don’t know whether Trump will pull the US out of the Paris climate agreement, it doesn’t bode well that scientists have announced the world could smash the warning target of 1.5°C (2.7°F) global warming in as little as nine years.
The study, published in the journal Geophysical Research Letters, suggests that the climate cycles of the Pacific Ocean could have been acting as a "temporary buffer" for the global temperature rise. And if the cycle changes into its positive phase, which the researchers think it may have done already, the global temperature is going to heat up much faster than it has been.
The Interdecadal Pacific Oscillation (IPO) is an ocean-atmosphere climate pattern that changes slowly over a period of 10-30 years and is detected as cool (negative) or warm (positive) surface waters. It has been in a negative phase since 1999, but the recent record-breaking warm years in 2014, 2015, and 2016 could indicate that it either has or is about to enter a positive phase.
The study shows how the last two positive phases, in 1925-1946 and 1977-1998, demonstrated a rapid increase in global temperature spikes, and how temperatures stalled during the negative phase recorded from 1947-1976. However, in the most recent negative phase, temperatures continued to climb, albeit slowly.
“Although the Earth has continued to warm during the temporary slowdown since around 2000, the reduced rate of warming in that period may have lulled us into a false sense of security,” said lead author Dr Ben Henley of the University of Melbourne in a statement. “The positive phase of the IPO will likely correct this slowdown. If so, we can expect an acceleration in global warming in the coming decades.”
Under the Paris agreement, 196 countries agreed to limit the global warming rise to no more than 1.5°C above pre-Industrial levels. 2016 was already 1.1°C warmer than the average from 1850-1900, according to the Met Office.
If the IPO is now positive, the researchers’ projections say we could be looking at accelerated heating over the next decade, possibly breaking the 1.5°C target by 2026.
It's looking increasingly unlikely that the Paris agreement target is going to be met, whether or not the IPO has entered a new phase, but the researchers say we shouldn't give up.
“Even if the IPO remains in a negative phase, our research shows we will likely see global temperatures break through the 1.5°C guardrail by 2031,” Dr Henley added. “Should we overshoot the 1.5°C limit, we must still aim to bring global temperatures back down and stabilize them at that level or lower.”