The National Snow and Ice Data Center (NSIDC) reports the rate of ice loss in the Arctic slowed in the first half of July, primarily because of a change in atmospheric circulation as the dipole anomaly, an atmospheric pattern that dominated the Arctic in June, broke down.

The report explains:

Through much of May and June, high pressure dominated the Beaufort Sea with low pressure over Siberia. Winds associated with this pattern, known as the dipole anomaly, helped speed up ice loss by pushing ice away from the coast and promoting melt.

However, the dipole anomaly pattern broke down in early July. In the first half of July, cyclones (low pressure systems) generated over northern Eurasia tracked eastward along the Siberian coast and then into the central Arctic Ocean, where they tend to stall. This cyclone pattern is quite common in summer. The low-pressure cells have brought cooler and cloudier conditions over the Arctic Ocean. They have also promoted a cyclonic (anticlockwise) sea ice motion, which acts to spread the existing ice over a larger area. All of these factors likely contributed to the slower rate of ice loss over the past few weeks.

In the last few days, high pressure has started to build again in the Beaufort Sea, but whether this will continue remains to be seen.

Still, Arctic sea ice extent at this time is the second lowest ever recorded, as seen in this chart from the Japan Aerospace Exploration Agency website, IJIS.

The National Snow and Ice Data Center (NSIDC) reports Arctic sea ice declined at the fastest rate ever recorded in June, and the average ice extent in June was the lowest in the satellite data record (from 1979 to 2010).

The previous record for the fastest rate of June decline was set in 1999. The linear rate of monthly decline for June over the 1979 to 2010 period is now 3.5% per decade.

Whether or not 2010 will see a new record low set for Arctic sea ice extent depends upon weather patterns. NSIDC explains:

The record low ice extent of September 2007 was influenced by a persistent atmospheric pressure pattern called the summer Arctic dipole anomaly (DA). The DA features unusually high pressure centered over the northern Beaufort Sea and unusually low pressure centered over the Kara Sea, along the Eurasian coast. In accord with Buys Ballot’s Law, this pattern causes winds to blow from the south along the Siberian coast, helping to push ice away from the coast and favoring strong melt. The DA pattern also promotes northerly winds in the Fram Strait region, helping to flush ice out of the Arctic Ocean into the North Atlantic. The DA pattern may also favor the import of warm ocean waters from the North Pacific that hastens ice melt.

June 2010 saw the return of the DA, but with the pressure centers shifted slightly compared to summer 2007. As a result, winds along the Siberian coastal sector are blowing more from the east rather than from the south. Whether or not the DA pattern persists through the rest of summer will bear strongly on whether a new record low in ice extent is set in September 2010.

A report in Science magazine brings together dozens of studies that collectively paint the dismal picture that the deterioration of ocean health is rapidly approaching the point where it may be irreversible.

Ove Hoegh-Guldberg, director of the Global Change Institute at the University of Queensland in Australia and a co-author of the report, says:

This is further evidence we are well on our way to the next great extinction event.

Important conclusions in the report, titled The Impact of Climate Change on the World’s Marine Ecosystems, include:

• The average temperature of the upper level of the oceans has increased more than 1 degree Fahrenheit during the past 100 years, and global ocean surface temperatures in January were the second warmest ever recorded for that month.
• Though the increase in acidity is slight, it represents a “major departure” from the geochemical conditions that have existed in the oceans for hundreds of thousands if not millions of years.
• Nutrient-poor “ocean deserts” in the Pacific and Atlantic oceans grew by 15 percent from 1998 to 2006.
• Oxygen concentrations are dropping off the Northwest U.S. coast and the coast of southern Africa, where dead zones appear regularly. There is paleontological evidence that declining oxygen levels in the oceans played a major role in at least four or five mass extinctions.
• Since the early 1980s, the production of phytoplankton, a crucial part of the food chain, has declined 6 percent, with 70 percent of the decline found in the northern parts of the oceans. Scientists also found that phytoplankton are becoming smaller.

Here’s the abstract:

Marine ecosystems are centrally important to the biology of the planet, yet a comprehensive understanding of how anthropogenic climate change is affecting them has been poorly developed. Recent studies indicate that rapidly rising greenhouse gas concentrations are driving ocean systems toward conditions not seen for millions of years, with an associated risk of fundamental and irreversible ecological transformation. The impacts of anthropogenic climate change so far include decreased ocean productivity, altered food web dynamics, reduced abundance of habitat-forming species, shifting species distributions, and a greater incidence of disease. Although there is considerable uncertainty about the spatial and temporal details, climate change is clearly and fundamentally altering ocean ecosystems. Further change will continue to create enormous challenges and costs for societies worldwide, particularly those in developing countries.

It’s approaching the end of June, and Arctic sea ice is continuing to melt precipitously.  Arctic sea ice is shrinking at a record pace both in extent . . .

. . . and in volume:

We’ve never seen anything like current conditions in the historical record.

A new paper in the journal Nature titled Robust warming of the global upper ocean concludes that the world’s oceans have been warming more than previously thought – and more than even climate models were suggesting.

RealClimate has posted this graph showing the measured warming as compared to previous and model estimates:

Basically, if the total flux of energy entering the Earth’s atmosphere is greater than energy losses, then has to go somewhere – and that somewhere is mainly the ocean. Other reservoirs for this excess energy, like the land surface or melting ice, are much smaller and are for most purposes negligible.

An article about the study by Jason Socrates Bardi quotes Kevin Trenberth of the National Center for Atmospheric Research in Boulder, Colorado (Trenberth was not involved with the study):

Ninety percent of the energy [trapped by increased greenhouse gases] goes into the ocean. It’s important to track this in order to properly understand what is happening in the climate system. If you dump heat in the ocean and it gets moved around and reappears somewhere, it has consequences in terms of the weather patterns.

Another new study in the journal Oceanography titled The Volume of Earth’s Ocean finds the Earth’s ocean is smaller  than the most recent published estimates, by a volume equivalent to 500 times the Great Lakes or five times the Gulf of Mexico. The study’s authors used satellite altimetry data to better measure ocean depth and thus to more accurately estimate the ocean’s volume.

This transcript of a talk by Jeremy Jackson about how we wrecked the ocean, posted at The Oil Drum,  may be the saddest thing I’ve ever read.

Jackson describes himself as “an ecologist, mostly a coral reef ecologist.” He talks about the degradation of coral reefs and ocean ecosystems that he’s seen in his lifetime. Scientists used to believe that coral reefs and oceans were infinitely resilient – after all, they’ve survived for untold millennia. But they have succumbed to but a few decades of abuse by humans.

And we got it all wrong. And the reason was because of overfishing, and the fact that a last common-grazer, a sea urchin, died. And within a few months after that sea urchin dying, the seaweed started to grow. And that is the same reef. That’s the same reef 15 years ago. That’s the same reef today. The coral reefs of the north coast of Jamaica have a few percent live coral cover and a lot of seaweed and slime. And that’s more or less the story of the coral reefs of the Caribbean, and increasingly, tragically, the coral reefs worldwide.

Now, that’s my little, depressing story. All of us in our 60s and 70s have comparable depressing stories. There are tens of thousands of those stories out there. And it’s really hard to conjure up much of a sense of well-being, because it just keeps getting worse. And the reason it keeps getting worse is that, after a natural catastrophe, like a hurricane, it used to be that there was some kind of successional sequence of recovery, but what’s going on now is that overfishing and pollution and climate change are all interacting in a way that prevents that. And so I’m going to sort of go through and talk about those three kinds of things.

Jackson does go on to talk about those things. About fish disappearing. About habitat destruction, the sea floor being turned into a desert of mud. About biological pollution and seas becoming poisonous. About warming oceans and dying corals. And about the synergies among these tragedies, the positive feedback loops, that are making the whole of the catastrophe vastly greater than the sum of the parts.

Jackson’s prognosis?

So what are the oceans going to be like in 20 or 50 years? Well, there won’t be any fish except for minnows, and the water will be pretty dirty, and all those kinds of things, and full of mercury, etc., etc. And dead-zones will get bigger and bigger, and they’ll start to merge. And we can imagine something like the dead-zonification of the global, coastal ocean. Then you sure won’t want to eat fish that were raised in it, because would be a kind of gastronomic Russian roulette. Sometimes you have a toxic bloom; sometimes you don’t. That doesn’t sell.

The really scary things though are the physical, chemical, oceanographic things that are happening. As the surface of the ocean gets warmer, the water is lighter when it’s warmer, it becomes harder and harder to turn the ocean over. We say, it becomes more strongly stratified. The consequence of that is that all those nutrients that fuel the great anchoveta fisheries, or the sardines of California, or in Peru, or whatever, those slow down, and those fisheries collapse. And, at the same time, water from the surface, which is rich in oxygen, doesn’t make it down, and the ocean turns into a desert.

The shame of being human is sometimes unbearable.

A recent post reported on scientists’ findings that Greenland’s glaciers are melting from the bottom up. Findings from another team of scientists help explain why: subtropical waters from warmer latitudes are reaching Greenland’s glaciers, driving melting and likely triggering an acceleration of ice loss.

Credit: Jack Cook, Woods Hole Oceanographic Institution

The research team, led by Fiamma Straneo, a physical oceanographer at Woods Hole Oceanographic Institution, found that subtropical waters are reaching Greenland’s glaciers, driving melting and likely triggering an acceleration of ice loss. Melting ice also means more fresh water in the ocean, which could flood into the North Atlantic and disrupt a global system of currents, known as the Ocean Conveyor.

Science Daily quotes Straneo:

This is the first time we’ve seen waters this warm in any of the fjords in Greenland. The subtropical waters are flowing through the fjord very quickly, so they can transport heat and drive melting at the end of the glacier.

The Greenland ice sheet’s contribution to sea level rise over the last decade has doubled due to increased melting and especially to the widespread acceleration of outlet glaciers.

The research teamconducted two extensive surveys during July and September of 2008 in Sermilik Fjord, a 100-kilometer long glacial fjord in East Greenland connecting Helheim Glacier with the Irminger Sea. In 2003 alone, Helheim Glacier retreated several kilometers and almost doubled its flow speed.  Deep inside the fjord, researchers found subtropical water as warm as 39 degrees Fahrenheit (4 degrees Celsius). The team also reconstructed seasonal temperatures on the shelf using data collected by 19 hooded seals tagged with satellite-linked temperature depth-recorders. The data revealed that the shelf waters warm from July to December, and that subtropical waters are present on the shelf year round.

The National Marine Fisheries Service (NMFS ) is considering listing corals as endangered species under the Endangered Species Act.  From the Federal Register:

[W]e initiate status reviews of 82 species of corals to determine if listing under the ESA is warranted.

In October 2009 NMFS received a petition from the Center for Biological Diversity to list 83 species of coral as threatened or endangered under the ESA. The petition asserts that synergistic threats of ocean warming, ocean acidification, and other impacts affect these species and that these global habitat threats are exacerbated by local habitat threats posed by ship traffic, dredging, coastal development, pollution, and agricultural and land use practices that increase sedimentation and nutrient loading. The petition states that immediate action is needed to reduce greenhouse gas concentrations to levels that do not jeopardize these species and requests that critical habitat be designated for these corals concurrent with listing under the ESA.

A species or subspecies is ‘‘endangered’’ if it is in danger of extinction throughout all or a significant portion of its range, and ‘‘threatened’’ if it is likely to become endangered within the foreseeable future throughout all or a significant portion of its range.

NMFS will have to “assess conservation measures to determine whether they ameliorate a species’ extinction risk” and, once critical habitat is designated, ensure that Federal agencies do not fund, authorize or carry out any actions that are likely to destroy or adversely modify that habitat.

Any area may be excluded from a critical habitat designation if the benefits of exclusion outweigh the benefits of designation, unless excluding that area “will result” in extinction of the species. So economic and national security considerations could trump the science.

So much for the “immediate action” that is needed to reduce greenhouse gas concentrations.

It’s nothing but Kabuki theater – highly stylized ritual rather meaningful action  or even honest discussion.

New NASA-led research shows that the melt season for Arctic sea ice has lengthened by an average of 20 days over the span of 28 years, or 6.4 days per decade.

The research team discovered that the melt season lengthened the most – more than 10 days per decade – in Hudson Bay, the East Greenland Sea, the Laptev and East Siberian Seas, and the Chukchi and Beaufort Seas.

Earlier melt means more heat can be absorbed by the open water, promoting more melting and later freeze-up dates — more than eight days per decade later in some areas.

Thorsten Markus of NASA’s Goddard Space Flight Center in Greenbelt, Md. explains how the feedback loop works:

This feedback process has always been present, yet with more extensive open water this feedback becomes even stronger and further boosts ice loss. Melt is starting earlier, but the trend towards a later freeze-up is even stronger because of this feedback effect.

Scientists have upped their estimates of the waves a “100 year event” might produce along the coast of the Pacific Northwest. Their findings heighten concerns for flooding, coastal erosion and structural damage.

Waves crawl up against the lower level of a structure in Neskowin, Oregon, during a storm in January, 2008. (Photo by Armand Thibault, Neskowin)

As recently as 1996, the maximum in ocean wave heights was estimated to be 33 feet. In a study just published online in the journal Coastal Engineering, scientists from Oregon State University and the Oregon Department of Geology and Mineral Industries conclude that the highest waves may be as much as 46 feet and the 100-year wave height could actually exceed 55 feet. Impacts of the bigger waves would dwarf impacts expected from sea level rise in coming decades.

Over the last few decades, increasing wave heights have had 2 – 3 times the impact of sea level rise in terms of erosion, flooding and damage. The largest wave height increases have occurred off the Washington and northern Oregon coast, with less increase in southern Oregon and nothing of significance south of central California.

Possible causes cited are changes in storm tracks, higher winds, more intense winter storms, or other factors probably related to global warming but also possibly related to periodic climate fluctuations such as the Pacific Decadal Oscillation. What is clear is that waves are getting bigger.

The significant rise in sea level expected over future decades and centuries will only add to the damage already being done by higher waves.