Shrinking Snowpacks Projected to Affect 2 Billion Lives in N. Hemisphere - International Business Times
The Ross Ice Shelf is much like the Rosetta Stone. The historic stone was inscribed in three different scripts; each telling the same story but in a different tongue. When matched together the information was enough to allow scholars to decode an ancient language. The Rosetta Project in Antarctica also brings together three different ‘scripts’, but in this case they written by three Earth systems; the ice, the ocean and the underlying bed each have a story to tell. Mapped together these three systems can be used to unlock the mysteries of Antarctic ice history in this region and help us to develop models for predicting future changes in Antarctic ice.
The multi-institutional project is multi-disciplinary in nature and takes advantage of the recently commissioned IcePod integrated ice imaging system as the main science platform. IcePod is package of geophysical instruments packed into a 9 ft. container and loaded onto the large LC130 transport planes supporting science in the polar regions. Flown by the US Air National Guard these planes are the workhorses of the science program. A unique ‘arm’ that fits into the rear side-door of the plane is used to attach the IcePod outside the aircraft, allowing it to be used on both dedicated missions and flights of opportunity.
IcePod’s instruments include two radar to image through the ice, lidar to measure to the ice surface, cameras for surface images, and a magnetometer to better understand the tectonics and origin of the bed below the ice shelf. Together with the IcePod instruments the project will use two separate gravimeters in order to develop a bathymetric map of the seafloor under the ice shelf. Gravity is a critical data piece in this project as the radar is unable to image through the water under the ice shelf.
The Ross Ice Shelf is a thick slab of ice that serves to slow and collect ice as it flows off the Antarctic peninsula. Ross is the largest of the Antarctic ice shelves moving ice at rates of 1.5 to 3 meters/day. Somewhat triangular in shape, it is bounded by the West Antarctic ice sheet on the west, the East Antarctic ice sheet on the east, and the Ross sea along the front.
This three year project involves 36 separate flights in a two season field campaign. The first field season is underway now, and will focus on building the larger framework for the dense 10 km spaced grid of flights that is planned for the following season. As each day’s flights are logged they are being posted on our interactive website. You can follow our campaign by linking directly to this data portal to watch the grid develop. You can select the project proposed flight plan (v9) on the Data Map to get a complete look at the project plan. The end product will be a dense grid of flightlines evenly spaced and crossing with regular tie points.
First flights included two survey lines across the ice shelf. The most southern of the two lines was flown by IcePod in 2014 during commissioning flights, and by the NASA IceBridge project in 2013. These two flights provide a calibration line for the system. The northern line is the first new line for the project. The map also shows a small test flight for the equipment and a line up to South Pole that was a piggy back flight with another mission of the plane.
You will note that flights originate from McMurdo so there is a dense radiating line from the base. Minna Bluff is a prominent volcanic promontory that sticks out close to MCM. The bluff was first identified by Capt. Scott in 1902 and is mentioned often in Antarctic exploration history.
Check the flight tracker daily for updated flight lines.
For more about this NSF and Moore Foundation funded project please check our project website: ROSSETTA
Margie Turrin is blogging for the IcePod team while they are in the field.
Many experts at Columbia University’s Earth Institute are attending or closely watching the Paris climate summit. These include world authorities on climate science, politics, law, natural resources, national security, health and other fields, who can offer expert analysis to journalists. Also, this week we start our Paris Climate Summit blog, with news, views, and scientific perspective from our staff. Below, a guide to resources that journalists covering the summit can tap.
The Paris Climate Summit A frequently updated blog from Earth Institute experts with explainers, commentary and other features.
Recent Climate Research The top Earth Institute scientific papers from 2015 and previous recent years.
Milestones in Climate Science A 60-year timeline of studies from Lamont-Doherty Earth Observatory that have shaped modern climate science.
Copenhagen Climate Conference 2009 Our blog from the last major summit provides historical perspective.
(Not an exhaustive list. *Denotes person attending the summit.)
*Peter deMenocal, professor, Lamont-Doherty Earth Observatory. Paleoclimatologist DeMenocal leads the observatory’s new Center for Climate and Life, which will examine globally how climate change affects ecosystems and human sustainability.
Jason Smerdon is a Lamont-Doherty climate researcher and educator who co-directs the Earth Institute’s undergraduate sustainable development program.
Gavin Schmidt directs the NASA Goddard Institute for Space Studies. He is a leading communicator on the fundamentals of climate science, and the implications.
*Scott Barrett, Earth Institute professor of natural resources; expert in dynamics of transnational negotiations, treaties and conflict resolution, especially climate. Barrett is coeditor of a new e-book prepared especially for the summit.
*Michael Gerrard, director, Sabin Center for Climate Change Law, leader in the study of climate’s legal implications on state, national and international levels.
Michael Burger, executive director, Sabin Center for Climate Change Law, consults internationally on efforts to reduce carbon emissions, and on climate adaptation.
Steven Cohen, Earth Institute executive director, comments frequently on political developments surrounding climate and sustainable development.
Solutions, adaptations, sustainable development
*Lisa Goddard, director, International Research Institute for Climate and Society (IRI), which works with governments around the world to predict and adapt to medium-term climate swings.
*Cynthia Rosenzweig, Earth Institute senior research scientist, is a pioneer in studying how cities can adapt to climate change.
*Guido Schmidt-Traub, executive director, Sustainable Development Solutions Network. SDSN is a UN effort hosted by the Earth Institute that mobilizes teams across the world to solve global challenges, including climate change.
*Laura Segafredo manages SDSN’s Deep Decarbonization Pathways Project, a global collaboration of energy researchers charting steps for nations to cut emissions.
Upmanu Lall directs the Columbia Water Center, which tackles water-supply challenges and their relation to climate across the world.
Pedro Sanchez, director, Agriculture and Food Security Center, helps direct multiple projects in developing countries to ensure a robust food supply in changing conditions.
Shahid Naeem, director, Earth Institute Center for Environmental Sustainability, is an ecologist who deals with issues of conservation and biodiversity.
Marc Levy, deputy director, Center for International Earth Science Information Network (CIESIN), is a political scientist who studies the human dimensions of environmental change, including climate’s potential for violent conflict.
Alexander deSherbinin, CIESIN senior researcher, maps out the human consequences of climate change, including potential large-scale population migrations.
*Madeleine Thomson, IRI senior researcher, works to understand the health effects of climate, and help provide adaptations.
*Patrick Kinney, Earth Institute professor based at Mailman School of Public Health, studies the health effects of climate change, especially in cities.
Anthony Annett, an economist, leads the Earth Institute’s initiative to engage religious communities with climate and sustainable-development issues.
*Ben Orlove, anthropologist and co-director of the Center for Research on Environmental Decisions, studies how the public apprehends climate change issues.
# # #
More information: Kevin Krajick, Senior editor, science news, The Earth Institute email@example.com 212-854-9729
The storms of the past week cleared most of the pack ice out of Arthur Harbor, although the land fast ice that we’ve been sampling from has survived. In anticipation of the start of the boating season there was a flurry of activity yesterday as station personnel cleared off the boat ramp and got the zodiacs ready. Unfortunately Jamie and I didn’t think to start the time lapse below until yesterday afternoon after most of the three-ring circus had died down, but you still get a sense of the activity.
There are two science groups waiting to start boating operations; our group and a group of penguin researchers (aka “the birders”). Both groups are part of the Palmer LTER. While we will spend the summer investigating water column processes however, the birders will spend their summer visiting the various penguin rookeries and maintaining a remarkable long term dataset of penguin population.
The birders were supposed to get their final zodiac training today, but although the harbor is clear of ice the winds are back up (gusting around 30 kts at the moment) so everything is getting shifted back. In the meantime we will have a late night sampling another time point from the experiment that we started on Tuesday. As I described in the previous post, for this experiment we are making use of the highly unusual ice conditions to study what happens to the microbial community when the ice is suddenly removed (as has happened to much of Arthur Harbor and the surrounding area in the last week). Although we won’t know the results of most of our analyses for several months, we can make some interesting qualitative observations as the experiment progresses.
One of the interesting observations so far was the initial condition of the microbial community. During a down moment yesterday I took a look at water from just 24 hours into our experiment to see what was growing (so this isn’t exactly the initial condition, but a close approximation of it). What we found really surprised me. Here are a couple of images that illustrate the phytoplankton community in our experiment:
The traditional wisdom would suggest that the spring phytoplankton bloom should start with diatoms. Following the initial diatom bloom there are successive, mixed blooms of haptophytes, cryptophytes, dinoflagellates, and other groups of phytoplankton. Observations from this time of year are very sparse however, so it is difficult to know if we are seeing something that is unique or the normal phytoplankton assemblage for this time of year. The composition of the phytoplankton assemblage is not merely academic; it dictates how carbon will flow through the food web in a given season. Large diatoms for example, are easily feed upon by krill, resulting in high krill biomass and more and more healthy top predators (e.g. penguins, seals, and whales). Smaller phytoplankton (like cryptophytes) produce a more complex food web that might ultimately channel less carbon to the top trophic levels. We will have to wait and see how the situation plays out this year…
During the Copenhagen climate meetings in 2009, I posted a piece in the Huffington Post assessing the conference. At that time I observed that:
“There is a broad consensus about the need for reductions in the emissions that cause global warming. Copenhagen is providing the entire world a crash course in climate science and policy. Over the past decade, the politics of national and global climate policy has shifted from the fringes of the public policy agenda to the center. The real story of Copenhagen is the maturation of this key issue of global environmental policy. … Climate change is just the first global environmental problem we have come to understand. At Copenhagen we are barely discussing the other global environmental issues such as species extinction, the destruction of the oceans and degraded fresh water supplies. But we could.”
As we approach the Paris version of these endless talks, COP21, to be held next month, it’s fair to ask: What has changed over the past six years, and did Copenhagen stimulate any of these changes?
What has changed is the broad consensus on climate change has broadened, and recent polls show that even Republicans in the United States understand the nature of the problem. Globally, individual nations have volunteered greenhouse gas reduction targets in anticipation of the Paris meetings. Unlike Copenhagen, where calls for mandatory reductions and transfer payments to the developing world caused the collapse of any potential agreements, the world community seems more realistic as it approaches the Paris meetings. An agreement that codifies the reductions already pledged seems within reach, even if its value is more symbolic than real.
There remains a possibility that the call for transfer payments from wealthy nations to developing nations could disrupt the effort at building a global consensus. Previous aid promises were not fulfilled, and there is some political pressure to get the issue back on the global agenda. One of the major changes since 2009 is the clear perception that some nations once classified as developing, such as China, Brazil and India, can no longer be thought of in that way. While this was also the case in 2009, six years later, they are clearly in a category of their own.
My own view of the Paris talks and the ones that came before is that they have value, but it is important to understand their inherent limits. The climate issue is really an issue of the energy base of a nation’s economy. Modern economies require energy, and economic development depends on plentiful, reliable, reasonably priced energy. The issue is so central to economic growth and the stability of political regimes that no nation state will fundamentally limit its flexibility in delivering energy for any reason. It is central to sovereignty in the modern world. But communicating the dangers of fossil fuels and the need to transition to a renewable energy based economy is something these meetings have achieved, and the importance of that achievement should not be underestimated.
The climate issue seems to generate a high level of ideologically based politics, emotional rhetoric and political symbolism. It is time to move past symbols to pragmatism and political reality. We need to move toward an acceptance of nine fundamentals if we are to address the climate change crisis:
- Human induced climate change is real, already underway and will continue into the future.
- We cannot precisely predict the future impact of climate change on human settlements and economic well-being.
- Fossil fuels are the largest single generator of greenhouse gases.
- Our economic way of life and therefore the political stability of our world are highly dependent on energy that mainly comes from fossil fuels.
- The transition from fossil fuels to renewable energy is necessary but will take decades to accomplish.
- Reducing the use of fossil fuels by raising the price of these fuels is unlikely to achieve political support or be supported by the world’s governments.
- Reducing the use of fossil fuels by developing lower priced, reliable and renewable sources of energy requires additional technological development.
- Reduced energy costs will have great political appeal and positive economic impact.
- The increased use of current renewable energy technologies will be facilitated by government policy to attract capital and reduce the price of energy.
In my view, the battles over oil pipelines, fracking and divesting capital from fossil fuel companies are symbolic battles that serve to distract us from the operational issues that will facilitate the transition to a renewable energy economy. One issue to engage in is the coming battle to renew the favorable tax treatment of renewable energy in the U.S., now slated to end in December 2016. Ending that tax expenditure would slow down the growth of the solar and wind industry and have an immediate and dramatic impact on the production of greenhouse gases.
The Department of Energy and the National Science Foundation’s research budget for renewable energy technologies needs to be increased dramatically. The federal government should take the lead in purchasing electric vehicles and installing renewable energy. A federal fund to restore and build infrastructure will probably appear on the federal agenda during the next decade. Some part of that funding should be devoted to upgrading the electric grid to make it smarter and more efficient, funding public charging stations for electric vehicles, funding mass transit, and providing resources to make coastal infrastructure more resilient and better able to adapt to the impact of climate change.
The action required to transition off of fossil fuels and other single-use resources requires a sophisticated partnership between the public and private sectors.
The greatest danger to America’s transition to a renewable resource based economy is not industry, which will make plenty of money off of this transition, or the public, which appears ready to move, but the anti-government ideology that continues to paralyze our federal government.
The action required to transition off of fossil fuels and other single-use resources requires a sophisticated partnership between the public and private sectors. There will be some instances when the work that needs to be done—for example, basic research or infrastructure finance—will require federal funds. There will be other instances when the tax code or other incentives will be needed to attract private capital and companies into the market. And there will be even more instances when government action is not needed, and the best thing government can do is get out of the way and let the private sector act. By sophisticated partnership, I mean one that is guided by results-oriented pragmatism rather than symbols and ideology.
The climate talks in Paris will focus attention on the climate issue and increase understanding of the nature of the problem. Then the spotlight shifts to nations and cities, and hopefully from talk and chit-chat to funding and action. There are many signs that the transition from fossil fuels has begun. The speed of that transition is at issue and will require creativity, consensus and cash to be completed.
This post is one in a series reflecting on what has changed since the climate talks of 2009 in Copenhagen.
Editors’ note: This is the first in a series of posts on the 2015 Paris climate summit. You can follow all of our coverage on a special State of the Planet feature page.
What is it?
COP21, the 2015 United Nations Climate Change Conference, will be held outside of Paris in Le Bourget, France, from Nov. 30 to Dec. 11. It is called COP21 because it is the 21st annual meeting of the Conference of Parties to the 1992 United Nations Framework Convention on Climate Change. The parties meet each year to assess their progress in dealing with climate change; its objective is to achieve “stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.”
The 195 countries who make up the UN Framework Convention on Climate Change will send over 40,000 delegates to the talks in Paris. At least 80 world leaders will attend, including the leaders of Germany, South Africa, Brazil and England, and those of the three biggest carbon emitting countries: President Barack Obama from the United States, Chinese President Xi Jinping and Indian Prime Minister Narendra Modi.
What is the goal?
The goal of COP21 is to negotiate a new international climate change agreement that can keep the average global temperature rise below 2° C by 2100 compared to pre-industrial levels. The agreement will be universal and include pledges from the parties to limit and reduce greenhouse gases, implement strategies to adapt to the impacts of climate change, and commit financial support to help developing countries deal with climate change. The agreement will also likely establish five-year reviews to make sure countries are keeping their commitments and to ratchet up emissions reduction targets in order to meet the 2˚C goal.
Why does it matter?
Human activities have generated greenhouse gases—carbon dioxide, methane, nitrous oxide and fluorinated gases—that have collected in the atmosphere and warmed the planet. Between 1990 and 2014, global greenhouse gases increased 36 percent. In 2011, Asia, Europe and the United States were responsible for 82 percent of total greenhouse gas emissions. Some of the carbon dioxide that we have already pumped into the atmosphere will remain there for hundreds of years.
The increase in greenhouse gases over the last 100 years has so far caused average global temperatures to rise .85˚C. Data for 2015 from the Met Office, the United Kingdom’s national weather service, shows that Earth’s global mean temperature will reach 1˚C above pre-industrial levels for the first time this year. While this does not sound like much, we are already feeling the effects of this warming with more extreme heat, heavy downpours, increased wildfires, insect outbreaks, loss of glaciers and sea ice, sea level rise and flooding.
Scientists and over 100 nations have agreed that limiting the global temperature rise to 2˚C is critical to avoiding more catastrophic climate change effects. According to the World Resources Institute, if we continue on a “business as usual” trajectory of generating greenhouse gases, we will reach 2˚C by 2045. This will increase the risk of sea level rise, intensify wildfires and make them more frequent, exacerbate heavy precipitation events and the severity of droughts, acidify the oceans, cause extinction of animal species and jeopardize our food supplies. With each degree above the 2˚C limit, the impacts of climate change will be more severe and the risks greater that tipping points could be passed, resulting in abrupt and irreversible changes in the global climate system.
In May, a UN Framework Convention on Climate Change report concluded that 1.5˚C would be a preferable limit, but would require a faster reduction of energy demand and an immediate scaling up of low-carbon technologies to curb greenhouse gases.
When does COP21 go into effect?
In 1997, at COP3, 192 parties adopted the Kyoto Protocol (the United States did not ratify the protocol), which legally bound developed countries to reduce their emissions. Kyoto’s first commitment period went from 2008 to 2012. A second commitment period, known as the Doha Amendment, began in 2013 and ends in 2020. The COP21 agreement will take effect in 2020 when the Kyoto Protocol ends.
How will it work?
At COP15 in Copenhagen in 2009, the 195 countries involved in the UN Framework Convention on Climate Change pledged to reduce their greenhouse gas emissions by 2025-2030.
Ahead of COP21, all the states were invited to submit their “Intended Nationally Determined Contributions” that indicate what actions the countries will take to reduce their emissions. Each plan takes into account a country’s particular circumstances and capabilities, and may address adaptation to climate change impacts, and what support they will need from, or be willing to give to other countries.
One hundred-thirty-one of these “intended contributions” have been submitted. Here are a few examples.
The United States has pledged to reduce greenhouse gas emissions 26 to 28 percent below its 2005 levels by 2025, with best efforts to reduce emissions by 28 percent. Strategies to achieve the goal include the U.S. Environmental Protection Agency’s regulations to cut carbon pollution from new and existing power plants, tighter fuel economy standards for light and heavy-duty vehicles, and the development of standards to address methane emissions from landfills and oil and gas production.
China pledges that its carbon emissions will peak by 2030 or sooner if possible, and that the country will reduce carbon dioxide emissions for each unit of Gross Domestic Product (its “emissions intensity”) by 60 to 65 percent from 2005 levels, derive 20 percent of energy from non-fossil fuels, plant more forests and improve the country’s adaptation to climate change impacts.
India intends to reduce the emissions intensity of its GDP by 33 to 35 percent by 2030 from 2005 levels, increase forest and tree cover to provide additional carbon sinks and generate 40 percent of its electricity from non-fossil fuel sources by 2030 with help from the Green Climate Fund. (The Green Climate Fund was established by 194 nations in 2010 with the goal of raising $100 billion a year by 2020 to assist developing countries deal with climate change.)
Brazil will reduce its greenhouse gas emissions 37 percent below 2005 levels by 2025, then by 43 percent below 2005 levels by 2030. Strategies to achieve this include using renewable resources for 45 percent of its energy by 2030, stopping illegal deforestation by 2030, restoring forests and developing sustainable agriculture. It will also implement adaptation policies to make its population, ecosystems, infrastructure and production systems more resilient.
The European Union has committed to reduce greenhouse gas emissions 40 percent from 1990 levels by 2030, in part by getting 27 percent of its energy from renewable energy resources and improving energy efficiency 27 percent by 2030.
Are the climate pledges ambitious enough to meet the goal?
The Climate Action Tracker, an independent scientific analysis, estimates that the climate pledges submitted so far will result in an increase of 2.7˚C of warming by 2100. This is an improvement over the worst-case scenario of a 4.5 to 6° C increase, which is what scientists estimate will result if we continue with business as usual; but it does not get us where we need to go.
However, the goal of remaining under the 2° C mark is targeted for 2100; these first climate pledges extend to 2025 or 2030. Much greater emissions reduction efforts will be needed after 2025 and 2030 to achieve the 2˚C limit. So a five-year periodic review mechanism will be critical to spur countries to set increasingly ambitious goals to reduce emissions.
What would a successful COP21 look like?
COP21 may or may not produce a treaty that legally binds countries to meet their emissions targets. If it does not, this should not be considered a failing, since legally binding treaties can cause countries to make overly modest commitments for fear of falling short, or opt out altogether.
COP21 will be considered a success if it:
- Results in countries agreeing on shared long-term goals to reduce carbon emissions and work towards climate resilience.
- Recognizes that all countries must take action.
- Creates a climate financing arrangement that is acceptable to both developed and developing countries.
- Establishes five-year reviews to encourage countries to continually set more ambitious emissions reduction goals.
- Ensures that countries are transparent about their progress and actions through an effective reporting and verification process.
Why should you care?
COP21 is the best opportunity for the world to finally slow the rate of climate change. Its outcome will affect our lives and those of our children and grandchildren. If successful, COP21 will hopefully help us avert the most disastrous and potentially irreversible effects of climate change. As President Obama said, “We are the first generation to feel the impact of climate change, and the last generation that can do something about it.”
The Laurence M. Gould departed for Punta Arenas last night, taking Colleen with it and leaving Jamie and I on our own until reinforcements arrive in two weeks (you can check out Jamie’s blog here for more on what we’re up to this season). That should work out fine although we’ll be very busy on sampling days – when and if we get sampling days. We were supposed to get out today but the weather isn’t cooperating.
Shortly after the Gould departed the wind started to increase. Right now the Gould is getting 50 kt winds at the southern edge of the Drake Passage (sorry Colleen!), we’re getting a steady 35 kt wind the blew all night and should last through today. I’m nervous about what that will do to our sampling plan. So far the land fast ice where our ice station is has held together; it’s a nearly a meter thick and pretty well anchored to the land. Sometime this season it’s going to give out though, and I’m hoping that we can sample from it a couple more times before that happens.
The flip side is that when the ice goes away we’ll be able to start using the zodiacs to sample at our regular stations, at least until the ice blows back in. The worst case scenario is being in the awkward position of too much ice for the zodiacs, but no solid land fast ice from which to sample. To get an idea of how fast things can change compare the ice conditions in the following pictures to the conditions when the Gould departed:
The fast departure of the ice underscores an important ecological concept that is central to this region. The timing of the switch from ice covered to open water conditions has a major impact on the strength and timing of the spring phytoplankton bloom; the annual ecological event from which everything else derives (think of it like a burst of new green grass in the Serengeti).
In the springtime Antarctic phytoplankton are limited in growth only by the absence of light. Nutrients have been replenishing all winter, there are no grazers around (yet), and the phytoplankton are relatively indifferent to temperature. Right now at Palmer Station we have nearly 18 hours of daylight, what keeps the phytoplankton bloom from exploding right now is the ice. Only 6 % of the light that hits the surface of the fast ice in Arthur Harbor is making its way down into the water. That’s enough to support the growth of specialized ice algae and low-light adapted phytoplankton just below the ice, but not a major bloom deeper in the water column. At just 10 m depth only about 0.01 % of the light that hits the surface remains; it is essentially totally dark.
So as soon as the ice departs the phytoplankton are primed to start growing. In Arthur Harbor the wind is driving the ice away, does this mean a bloom is about to start? Not necessarily. For phytoplankton, what the wind gives it also takes away. A strong wind induces strong vertical mixing in the water column. This impact of vertical mixing on phytoplankton has been studied in places like the North Atlantic for a very long time. Some phytoplankton can swim, but none can swim fast enough to outpace vertical mixing. Under a stiff, sustained wind phytoplankton in the surface are mixed deep into the water column. If they don’t go too deep that’s fine. Below a certain point they can’t photosynthesize enough to meet their metabolic demands (we usually take this to be the 1 % light level), but like all organisms they have energy stores and can wait to get mixed back above this depth. Pushed deep enough however, at what we call the critical depth a phytoplankton cell has insufficient energy stores to make it back to the surface. Under these conditions, although phytoplankton may be growing at the surface, the formation of the bloom will be suppressed.
So what does this have to do with timing? It’s no surprise that the strongest storms happen in the winter. In low sea ice years, with less land fast ice and an earlier retreat of both land fast and pack ice, the surface of the Antarctic ocean is exposed to late winter storms and strong mixing. Phytoplankton that have been overwintering safely in the stable water column below the ice start to grow, but are constantly mixed down below the critical depth. Eventually this stock of phytoplankton is depleted (or much reduced), leaving insufficient numbers to initiate the bloom when conditions finally calm down. This idea has been explored in a number of studies, including this great 1998 paper led by Kevin Arrigo at Stanford and this 2006 study led by Hugh Ducklow at the Lamont-Doherty Earth Observatory. This latter study is particularly interesting because it implicates the Southern Annual Mode (SAM) in determining the strength of the spring bloom. As the plot at right shows it’s clear that SAM isn’t the only thing that determines ice duration, extent, and the strength of the bloom, but it has a clear and logical role.
More recent studies have extended the link between sea ice and SAM to higher trophic levels, including krill. One of my favorite Palmer LTER papers is this 2013 paper by Grace Saba et al., which does a great job of illustrating the link and exploring the idea in the context of climate change. A negative phase in the SAM during the winter and springs leads to low wind and high ice conditions (a double bonus for phytoplanton). These conditions set the stage for a strong bloom and good krill recruitment (a large number of juvenille krill being “recruited” to the sexually mature, adult size class). A positive SAM during the winter and spring leads to low ice, high wind, and a taxonomically different and overall smaller phytoplankon bloom. This leads to fewer krill with a direct negative impact on penguins, seals, seabirds, and whales.
This post is getting long (this is what happens when a sampling day gets weathered out) so I want to end by wrapping it back around to the current season. As I described in a previous post things are a little different this year. The SAM index has generally been positive with some dips into the negative. Only for the month of October was the mean SAM negative, and not very. Despite this there is a definite positive sea ice anomaly. This seems to be driven by the strong, persistent El Niño in the equatorial Pacific that shows no sign of abating any time soon. Regardless of SAM, ice conditions are good this year, in a few weeks we’ll see what that means for the spring bloom when the ice clears out for good!