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World climate on the brink of large-scale change, says international study

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By NewsGram Staff Writer

The global climate is on the verge of broad-scale change that could last for a number of decades, shows a study by British scientists.

The change is linked to cooling of the Atlantic, and is likely to bring drier summers in Britain and Ireland.

The study, which appeared in the journal Nature, is based on observational evidence of the link between ocean circulation and the decadal variability of sea surface temperatures called the Atlantic Multi-decadal Oscillation (AMO).

“Sea-surface temperatures in the Atlantic vary between warm and cold over time-scales of many decades. These variations have been shown to influence temperature, rainfall, drought and even the frequency of hurricanes in many regions of the world,” said lead author Gerard McCarthy from the National Oceanography Centre (NOC).

These climatic phases are the result of the movement of heat northwards by a system of ocean currents. This movement of heat changes the temperature of the sea surface, which has a profound impact on climate on time-scales of 20-30 years.

The strength of ocean currents has been measured by a network of sensors, called the RAPID array, which have been collecting data on the flow rate of the Atlantic meridonal overturning circulation (AMOC) for a decade. The authors used 100 years of sea level data, maintained by the National Oceanography Centre’s permanent service for mean sea level.

“By reconstructing ocean circulation over the last 100 years from tide gauges that measure sea level at the coast, we have been able to show, for the first time, observational evidence of the link between ocean circulation and the AMO,” said co-author Ivan Haigh, lecturer in coastal oceanography at the University of Southampton.

 

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Great Barrier Reef Facing Unprecedented Challenges Amid Serious Ecological Disturbances

In light of the report, the World Wide Fund for Nature-Australia called for urgent climate change action

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"The Great Barrier Reef is still beautiful and it is resilient, but it is facing unprecedented challenges," AIMS Chief Executive Officer Paul Hardisty said. Wikimedia Commons

The health of Australias Great Barrier Reef is facing unprecedented challenges amid serious ecological disturbances, a report released on Thursday said. Crown-of-thorns starfish outbreaks — which have decimated breeding populations of corals over large areas — coral bleaching and cyclones were among the “major disturbances” in the past five years that have caused a general decline in coral cover in the world’s largest living organism, Efe news quoted the report by the Australian Institute of Marine Science (AIMS) as saying.

“The Great Barrier Reef is still beautiful and it is resilient, but it is facing unprecedented challenges,” AIMS Chief Executive Officer Paul Hardisty said. The report added that chronic stressors such as high turbidity, higher ocean temperatures and changing ocean chemistry affect recovery rates and more frequent disturbances shorten periods of recovery time.

“We know reefs can recover given time and the right conditions, but there has been little relief from disturbances in recent years to allow significant recovery to occur,” AIMS Long Term Monitoring Program leader and ecologist Mike Emslie said.

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In light of the report, the World Wide Fund for Nature-Australia called for urgent climate change action. Wikimedia Commons

The decline was measured in the central and southern areas of the reef, while the northern region has stabilized. In light of the report, the World Wide Fund for Nature-Australia called for urgent climate change action. “Australia must urgently reduce its dependency on fossil fuels and rapidly speed up the transition to a renewable economy,” WWF-Australia Head of Oceans Richard Leck said.

ALSO READ: Global Warming Threatens UN Goals of Tackling Inequality, Conflicts

Last month, a Change.org campaign was launched to push for citizenship for the Great Barrier Reef. The petition demands the reef be given rights akin to that of humans, including the right to health, freedom from torture or inhuman treatment or punishment, the right to maintain own means of subsistence and the right to life.

The Great Barrier Reef, home to 400 types of coral, 1,500 species of fish and 4,000 varieties of molluscs, began to deteriorate in the 1990s due to the double impact of water warming and increased acidity due to more carbon dioxide in the atmosphere. (IANS)