Effects of ozone depletion felt in the tropics

June 13, 2017, University of Bern
In Rikitea, French Polynesia, precipitation increased by 50 percent between the 1960s and the 1990s. Climate simulations indicate that this trend will be reversed by the expected recovery of the ozone layer. Credit: commons.wikimedia.org

The hole in the ozone layer above Antarctica has more far-reaching consequences than previously assumed. A study by Bernese climate researchers has now shown that it even affects precipitation in the tropical regions of the Pacific, 10,000 kilometres away. This new finding demonstrates how the climates of extremely remote areas are linked.

The struggle to close the hole in the ozone that opens above the Antarctic each spring is seen as one of the greatest achievements of international environmental policy. In the late 1980s, the international community committed to drastically reducing the use of substances that deplete the ozone layer. This led to a steady recovery of the ozone layer above Antarctica, and in 2014, the World Meteorological Organization (WMO) announced that if this trend continued, recovery would be complete by the year 2050 at the latest.

Now, however, an international team of researchers led by the Oeschger Centre for Climate Change Research at the University of Bern has concluded that the depletion of the ozone layer has had previously unknown effects on the climate system. Researchers found that even rainfall in the tropical regions of the Pacific is affected by the ozone hole. "The fact that there are such connections in the climate system between places so far apart is fascinating. However, it is disturbing that people are responsible for this", says the Bernese climatologist Stefan Brönnimann, who headed the study that has just been published in the journal Environmental Research Letters.

Global impact of the ozone hole

Simulations with a range of different climate models and statistical analyses of observed data from the past 60 years show that the hole in the ozone layer causes a ridge to the east of New Zealand. From that point, a wavy circulation pattern extends over the South Pacific and causes an increase in precipitation in the heart of the South Pacific Convergence Zone, one of the most intense rain belts on earth. For example, precipitation between October and December in Rikitea, French Polynesia, increased by 50 percent between the 1960s and the 1990s. A large part of that increase was down to the hole in the ozone layer. This trend will reverse during the ozone hole recovery that will take place over the next decades: precipitation in the region will be decreasing again.

"Significant was known to affect the winds over the Southern Ocean", explains Stefan Brönnimann, "but the effect as far as the Tropics had not previously been demonstrated." The focus of previous investigations was on the impact of the on the subpolar latitudes and the southern mid-latitudes.

"Our study shows that depletion was in the past a key driver of climate change in the of the Pacific", says Stefan Brönnimann, "and in the same way, the recovery of the will also affect the climate in the future." Considering the impact of the greenhouse effect caused by carbon dioxide and other gases, the Bernese climatologist is concerned by this evidence of the huge impact of human activity on the regional on the other side of the world.

Explore further: Image: 2015 Antarctic ozone hole area approaches annual maximum

More information: Stefan Br?nnimann et al. Tropical circulation and precipitation response to ozone depletion and recovery, Environmental Research Letters (2017). DOI: 10.1088/1748-9326/aa7416

Related Stories

Is the ozone layer on the road to recovery?

February 10, 2013

(Phys.org)—Satellites show that the recent ozone hole over Antarctica was the smallest seen in the past decade. Long-term observations also reveal that Earth's ozone has been strengthening following international agreements ...

Antarctic ozone - not a hole lot worse or better

November 10, 2005

The Antarctic ozone hole this year was the fourth largest to be recorded since measurements of ozone depletion began in 1979. CSIRO Marine and Atmospheric Research's expert in ozone depletion, Dr Paul Fraser, says while the ...

Recommended for you

Nanoscale Lamb wave-driven motors in nonliquid environments

March 19, 2019

Light driven movement is challenging in nonliquid environments as micro-sized objects can experience strong dry adhesion to contact surfaces and resist movement. In a recent study, Jinsheng Lu and co-workers at the College ...

OSIRIS-REx reveals asteroid Bennu has big surprises

March 19, 2019

A NASA spacecraft that will return a sample of a near-Earth asteroid named Bennu to Earth in 2023 made the first-ever close-up observations of particle plumes erupting from an asteroid's surface. Bennu also revealed itself ...

Levitating objects with light

March 19, 2019

Researchers at Caltech have designed a way to levitate and propel objects using only light, by creating specific nanoscale patterning on the objects' surfaces.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.