climate change tagged posts

Some coral populations already have genetic variants necessary to tolerate warm ocean waters, and humans can help to spread these genes, a team of scientists from The University of Texas at Austin, the Australian Institute of Marine Science and Oregon State University has found.

The discovery has implications for many reefs now threatened by global warming and shows for the first time that mixing and matching corals from different latitudes may boost reef survival. The findings are published this week in the journal Science.

The researchers crossed corals from naturally warmer areas of the Great Barrier Reef in Australia with corals from a cooler latitude nearly 300 miles to the south...

The threat of major coral bleaching in the Great Barrier Reef looks to be receding with the onset of stormier weather including the formation of the first tropical cyclone of the season likely to cross the coast. Sea temperatures are warmer than average from about Townsville all the way down the coast to the NSW-Victorian border, creating one of the components for coral stress.

Unusually calm conditions over much of the Great Barrier Reef have also contributed to setting up possible bleaching events as clearer water lets more sunlight reach the sea floor. During bleaching events, corals expel the algae that provide as much as 90 per cent of the energy they need to grow and reproduce, killing some of them.

“Heat makes light toxic,” Andrew Baird, a coral reef ecologist at James Cook Univers...

The deeper half of the ocean did not get measurably warmer in the last decade, but surface layers have been warming faster than we thought since the 1970s, two new studies suggest. Because the sea absorbs 90% of the heat caused by human activity, its warmth is a central concern in climate science. The new work suggests that shallow layers bear the brunt of ocean warming.

Scientists compared temperature data, satellite measurements of sea level, and results from climate models. Both the papers appear in the journal Nature Climate Change.

Underestimation

Specifically in the Southern Hemisphere where fewer measurements have been made, a team of researchers from the Lawrence Livermore National Laboratory in California investigated long-term warming in the top 700m of the ocean.

They wanted t...

Climate change is impacting the world’s coral reefs, threatening the stability of both the oceanic eco-systems where they are found as well as nearby coasts. Now, a recent discovery by Israeli researchers may help pinpoint a way to help protect the massive underwater structures as waters grow warmer and more acidic in the years to come.

“We know the value of reefs, the massive calcium carbonate constructions that act as wave breakers, and protect against floods, erosion, hurricanes, and typhoons,” Yehuda Benayahu, the Israel Cohen Chair in Environmental Zoology at Tel Aviv University, said. “While alive, they provide habitats for thousands of living organisms, from sea urchins to clams, algae to fish. Reefs are also economically important in regions like Eilat or the Caribbean.”

Coral reef fishes exposed to acid oceans lose their sense of smell – and their sense of caution – and are more likely to fall prey to natural enemies, according to new research in Nature Climate Change. The finding is based on observations of the behaviour of four species at a reef off the coasts of Papua New Guinea where natural carbon dioxide seeps out of the rock, and confirms a series of other such studies in the last year.

A cool volcanic discharge in the reef has served as a natural laboratory for years: water in the region reaches an average pH of 7.8. This standard measure of acidity is co-incidentally the level predicted for all the world’s oceans by 2100, as atmospheric carbon dioxide levels continue to rise, according to the Intergovernmental Panel on Climate Change. www...

Much attention has been focused on the effects of climate change on forests, farms, freshwater sources and the economy. But what about the ocean? Even with its vast capacity to absorb heat and carbon dioxide, the physical impacts of climate change on the ocean are now clear — and dramatic.

As early as 1990, coral reef expert Tom Goreau and I pointed out that mass coral-bleaching events that scientists observed during the 1980s were probably due to anomalously warm temperatures related to climate change. Mass coral bleaching results in the starvation, shrinkage and death of the corals that support the thousands of species that live on coral reefs. In addition, many fish species have moved toward the planet’s poles in response to ocean warming, disrupting fisheries around the world.

Ri...

US President Barack Obama has laid out a package of measures aimed at curbing climate change, including limits on emissions from power plants. He also unveiled plans for an expansion of renewable energy projects, improved flood resilience and calls for an international climate deal. Administration officials had earlier rejected the idea of a “carbon tax”. President Obama pledged in his inaugural address in January to act on climate change in his second term.

‘Moral obligation’

Speaking at Georgetown University in Washington DC, President Obama said: “As a president, as a father and as an American, I am here to say we need to act.” President Obama mocked critics who contend climate change is not a threat.

“I don’t have much patience for anyone who denies that this challenge is real,” he...