Friday, April 1, 2016

Is Global Warming Killing Earth's Oceans?


NOT A GOOD TIME TO BE A FISH


As the oceans continue to warm, it is crucial to understand how our actions are affecting marine life. Some species will not be able to withstand the increase in temperature. The most recent U.S. National Climate Change Assessment projects that outbreaks of marine diseases are likely to increase in frequency and severity as waters warm under climate change. Researchers are working around the world to determine whether and how species will survive disease events in our increasingly altered oceans.

The Conversation


Is global warming causing marine diseases to spread?





Global climate change is altering the world’s oceans in many ways. Some impacts have received wide coverage, such as shrinking Arctic sea ice, rising sea levels and ocean warming. However, as the oceans warm, marine scientists are observing other forms of damage.
My research focuses on diseases in marine ecosystems. Humans, animals and plants are all susceptible to diseases caused by bacteria, viruses, parasites and fungi. Marine diseases, however, are an emerging field.
Infectious agents have the potential to alter ocean life in many ways. Some threaten our food security by attacking important commercial species, such as salmon. Others, such as bacteria in oysters, may directly harm human health. Still others damage valuable marine ecosystems – most notably coral reefs.
To anticipate these potential problems, we need a better understanding of marine diseases and how climate change affects their emergence and spread.


Ten Times Faster Than a Hothouse Extinction 

The human fossil fuel emission is outrageous and unprecedented on geological timescales. An insult the Earth has never seen before. The pace we are emitting carbon into the atmosphere is just insane. We've known this for some time because the best of science can't find any time in all of Earth's geological history equalled what's happening now.
C02 emissions are about 150 times that of all the volcanoes on Earth, 10 times faster than the hothouse extinction that occurred some 60 million years ago. “If you look over the entire period, the only event with a massive carbon release that happened over a relatively short period of time is the Paleocene-Eocene Thermal Maximum. We don’t see anything even remotely comparable to what we humans are currently doing.”
The PETM Hothouse was amazingly bad. It wiped out half of all shellfish; it completely reversed ocean circulation and set up a stratified ocean state; peatlands and forests went up in mass conflagrations; terrible insect plagues swept the globe; it forced a mass poleward migration and widespread genetic alteration of mammals which were eventually reduced to dwarfism. 
Expected warming  this century is 10 to 200 times faster than during the PETM extinction event


Anthropogenic carbon release rate unprecedented during the past 66 million years




New cause of exceptional Greenland melt revealed



IMAGE

TORONTO, April 1, 2016 - A new study by researchers from Denmark and Canada's York University, published in Geophysical Research Letters, has found that the climate models commonly used to simulate melting of the Greenland ice sheet tend to underestimate the impact of exceptionally warm weather episodes on the ice sheet.
The study investigated the causes of ice melt during two exceptional melt episodes in 2012, which occurred from July 8 to 11 and from July 27 to 28. During these exceptional melt episodes, which can be regarded as an analogue to future climate, unusually warm and moist air was transported onto the ice sheet. During one episode, the researchers measured the ice sheet melting at more than 28 cm per day, the largest daily melt rate ever documented on the ice sheet. While the two brief melt episodes only lasted six days combined, or six per cent of the melt season, they contributed to 14 per cent of the total melt.


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