OCEANS WARMING

WARMING OCEANS

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Human activities are releasing nearly 10 Gegatons of Carbon (about 36 Billion tons of CO2) into the atmosphere every year, driving atmospheric CO2 concentrations to 400 parts per million (ppm) from their original pre-industrial levels of 280 ppm. This increase in CO2 and other greenhouse gases concentrations traps additional energy in the earth's climate system. What happens to this "extra" energy (0.5-1 watt/m2) remains a mystery to many outside the field of climate and sciences.

Oceans have absorbed 20 times more heat than the atmosphere over the last 50 years resulting in warmer oceans, melting ice caps and rising sea levels.

The recorded increases in ocean temperatures extend well beyond that of natural climate variation. Because of this rise some models suggest that it is likely to warm the air another degree Fahrenheit (0.55° Celsius) worldwide over the coming decades.

Sea water 1,500 feet below the surface is warming as well as surface waters. These increases in temperature lie well outside the bounds of natural variation.

Where land temperatures are easier to measure that the sea, scientists use several methods to create an ocean record.

1. Dropped from ships or airplanes, probes gauging the ocean's conductivity, temperature, and density provide nearly continuous surface-to-bottom measurements at specific times. However, these probes rarely reoccupy an exact location.

2. Remote vehicles can measure the temperature of deep ocean waters, and periodically surface to transfer the information to satellites.

3. Moorings on the ocean bottom can measure temperatures at fixed distances above the bottom, until a ship retrieves the instruments - typically after a few months or years.

4. The most common measurements, however, are taken at the sea surface. Scientists combine these measurements with land surface measurements to calculate the global average temperature.

5. Scientists also know that ocean temperatures are rising because warm-water species are moving into areas that were previously too cold, while cool-water and cold-water species are migrating closer to the poles.

PLASTIC - While measuring the temperature of the sea in the arctic, scientists noticed how much plastic was in the water. With acid oceans and climate change, we are really messing things up.

UC SANTA BARBARA FEB 2019 - WARM SEAS SCATTER FISH

Fish provide a vital source of protein for over half the world’s population, with over 56 million people employed by or subsisting on fisheries. But climate change is beginning to disrupt the complex, interconnected systems that underpin this major source of food.

A team of scientists led by Christopher Free, a postdoctoral scholar at UC Santa Barbara’s Bren School of Environmental Science & Management, has published an investigation of how warming waters may affect the productivity of fisheries. The results appear in the journal Science.

The study looked at historical abundance data for 124 species in 38 regions, which represents roughly one-third of the reported global catch. The researchers compared this data to records of ocean temperature and found that 8 percent of populations were significantly negatively impacted by warming, while 4 percent saw positive impacts. Overall, though, the losses outweigh the gains.

“We were surprised how strongly fish populations around the world have already been affected by warming,” said Free, “and that, among the populations we studied, the climate ‘losers’ outweigh the climate ‘winners.’”

CHRIS FREE - Chris developed his interest in quantitative ecology at Middlebury College where he received a BA in Conservation Biology and studied the population dynamics and sustainable management of tropical trees. After graduating, he continued this work with funding from the US Forest Service, worked on seabird conservation at Audubon Alaska, and worked as a fisheries field technician at the Dauphin Island Sea Lab. Chris did his PhD with Olaf Jensen at Rutgers University where he worked on small-scale fisheries management, data-limited stock assessment, and impacts of climate change on global fisheries. At SFG, Chris will be working to assess the impact of climate change and management reform on country-level fisheries health and profitability.

Region had the greatest influence on how fish responded to rising temperatures, according to the study. Species in the same region tended to respond in similar ways. Fishes in the same families also showed similarities in how they responded to changes. The researchers reasoned that related species would have similar traits and lifecycles, giving them similar strengths and vulnerabilities.

When examining how the availability of fish for food has changed from 1930 to 2010, the researchers saw the greatest losses in productivity in the Sea of Japan, North Sea, Iberian Coastal, Kuroshio Current and Celtic-Biscay Shelf ecoregions. On the other hand, the greatest gains occurred in the Labrador-Newfoundland region, Baltic Sea, Indian Ocean and Northeastern United States.

Although the changes in fisheries productivity have so far been small, there are vast regional discrepancies. For instance, East Asia has seen some of the largest warming-driven declines, with 15 to 35 percent reductions in fisheries productivity. “This means 15 to 35 percent less fish available for food and employment in a region with some of the fastest growing human populations in the world,” said Free. Mitigating the impacts of regional disparities will be a major challenge in the future.

These findings highlight the importance of accounting for the effects of climate change in fisheries management. This means coming up with new tools for assessing the size of fish populations, new strategies for setting catch limits that consider changing productivity, and new agreements for sharing catch between winning and losing regions, Free explained.

“Knowing exactly how fisheries will change under future warming is challenging, but we do know that failing to adapt to changing fisheries productivity will result in less food and fewer profits relative to today,” Free explained.

Preventing overfishing will be a critical part of addressing the threat that climate change poses to the world’s fisheries. “Overfishing presents a one-two punch,” said Free. It makes fish populations more vulnerable to warming, while warming hinders the recovery of overfished populations.

Free also stressed that ocean warming is just one of many processes affecting marine life and the industries that rely on it. Ocean acidification, falling oxygen levels and habitat loss will also impact marine life. More research is necessary to fully understand how climate change will affect fish populations and the livelihoods of people that depend on them.

ABSTRACT Climate change is altering habitats for marine fishes and invertebrates, but the net effect of these changes on potential food production is unknown. Researchers used temperature-dependent population models to measure the influence of warming on the productivity of 235 populations of 124 species in 38 ecoregions. Some populations responded significantly positively (n = 9 populations) and others responded significantly negatively (n = 19 populations) to warming, with the direction and magnitude of the response explained by ecoregion, taxonomy, life history, and exploitation history. Hindcasts indicate that the maximum sustainable yield of the evaluated populations decreased by 4.1% from 1930 to 2010, with five ecoregions experiencing losses of 15 to 35%. Outcomes of fisheries management—including long-term food provisioning—will be improved by accounting for changing productivity in a warmer ocean.

RUTGERS JUNE 13 2018 - Climate Change Means Fish Are Moving Faster Than Fishing Rules, Rutgers-Led Study Says

Researchers say out-of-date regulatory system hasn't kept up with the realities of global warming and shifting fish populations.

Climate change is forcing fish species to shift their habitats faster than the world’s system for allocating fish stocks, exacerbating international fisheries conflicts, according to a study led by a Rutgers University–New Brunswick researcher.

The study, published online in the journal Science today, showed for the first time that new fisheries are likely to appear in more than 70 countries all over the world as a result of climate change. History has shown that newly shared fisheries often spark conflict among nations.

Conflict leads to overfishing, which reduces the food, profit and employment fisheries can provide, and can also fracture international relations in other areas beyond fisheries. A future with lower greenhouse gas emissions, like the targets under the 2015 Paris climate agreement, would reduce the potential for conflict, the study says.

ROAMING FISHERIES - Rutgers University-New Brunswick Assistant Professor Malin Pinsky with a summer flounder. The ocean is a critical source of nutrition for billions of people, with potential to yield further food, profits, and employment in the future (1). But fisheries face a serious new challenge as climate change drives the ocean to conditions not experienced historically. Local, national, regional, and international fisheries are substantially underprepared for geographic shifts in marine animals driven by climate change over the coming decades. Fish and other animals have already shifted into new territory at a rate averaging 70 km per decade (2), and these shifts are expected to continue or accelerate (3). We show here that many species will likely shift across national and other political boundaries in the coming decades, creating the potential for conflict over newly shared resources.

Contact: Todd Bates, 848-932-0550 todd.bates@rutgers.edu

“Most people may not understand that the right to harvest particular species of fish is often decided by national and regional fisheries management bodies,” said Malin Pinsky, an assistant professor of ecology, evolution and natural resources in Rutgers–New Brunswick’s School of Environmental and Biological Sciences. “Those bodies have made the rules based on the notion that particular fish species live in particular waters and don’t move much. Well, they’re moving now because climate change is warming ocean temperatures.”

In a recent study, Pinsky and Rutgers postdoctoral associate James Morley reported that many commercially important fish species could move their ranges hundreds of miles northward in search of colder water. This movement has already begun, and the results have been highly disruptive for fisheries.

“Consider flounder, which have already shifted their range 250 miles farther north,” Pinsky said. “Federal fisheries rules have allocated many of those fish to fishers in North Carolina, and now they have to steam hundreds of extra miles to catch their flounder.”

Pinsky and his co-authors cite other examples of the disruption of fisheries causing international disputes, including the “mackerel war” between Iceland and the European Union (EU).

Under rules agreed to by EU member nations, fishers harvest a certain number of mackerel each year. But by 2007, those mackerel had begun to move to colder waters near Iceland, which is not an EU member. Iceland began fishing the sudden abundance of mackerel, but could not agree with the EU on sustainable fishing limits. The dispute became a trade war and is still ongoing. Lobster fishers from the United States and Canada have also come into conflict over the lobster fishery, which is also moving north from New England to the Canadian Maritime Provinces.

Given climate change, the movement of fish to new ranges is inevitable, but the conflicts over fish stocks are not, the study says. Governing bodies such as the one overseeing the EU’s fisheries might negotiate with neighboring fisheries organizations to take account of old fisheries moving out and new ones moving in. Pinsky and his co-authors suggest, for example, that governments might allow the trading of fishing permits or quotas across international boundaries.

“We need international agreements for the collaborative monitoring and sharing of fisheries as they move, much as the Antarctic conservation agreement has begun to do,” he said. The Antarctic management body known as CCAMLR cooperates closely with neighboring fisheries managers to share information about shared fisheries, including those that will continue to move.

The alternative to such agreements is grim, including overfishing and conflicts over fisheries that can spill over into international tensions over trade, borders and sovereignty.

“We have a chance to avoid conflict over fisheries that could escalate international tensions, threaten our food supply, and reduce profit and employment worldwide,” Pinsky said. “Avoiding fisheries conflicts and overfishing ultimately provides more fish, more food and more jobs for everyone.”

Study co-authors include researchers at the University of British Columbia, Utrecht University, Cardiff University, Stockholm University and James Cook University who are participating in the Nippon Foundation-University of British Columbia Nereus Program.

SOME INCONVENIENT FACTS:

Since 1955, over 90% of the excess heat trapped by greenhouse gases has been stored in the oceans (Figure from IPCC 5th Assessment Report). The remainder of this energy goes into melting sea ice, ice caps, and glaciers, and warming the continent's land mass. Only the smallest fraction of this thermal energy goes into warming the atmosphere. Humans thus, living at the interface of the land, ocean and atmosphere, only feel a sliver of the true warming cost of fossil fuel emissions.

This 90% of extra heat taken up by the ocean is mostly in the upper 700 meters (m) layer (about 60% of total excess heat), while 30% is stored in layers deeper than 700 m (IPCC 5th Assessment Report). The ocean absorbs most of this "anthropogenic heat" because:

Water has a high heat capacity: It takes much more heat to warm 1 liter of water than it does to warm the same volume of air (or most other substances).

The ocean is deep: The world's oceans cover 71% of the earth surface and are about 4 km deep on average. This represents a tremendous reservoir of heat.

The ocean is dynamic: Heat, carbon, oxygen and various other quantities exchanged with the atmosphere are mixed throughout the ocean through currents, internal waves, eddies, and various other circulation mechanisms.

The largest changes in ocean temperatures were observed in the upper 75 m, due to closer proximity to the atmosphere and the large mixing within this layer (IPCC 5th Assessment Report). As we trap more energy in the earth climate system, heat penetrates further into the ocean. Two important geographic areas where the atmosphere "communicates" with deeper layers of the ocean are the North Atlantic and the Southern Ocean. Because of their distinct atmospheric conditions and geographic settings, surface waters near the poles can be buried into deeper layers, bringing along their heat signatures, thus warming the interior of the ocean.

The complex interactions between continued emissions of greenhouse gases, consequent energy imbalance, and changes in the storage and transport properties of heat in the ocean will largely determine the speed and magnitude of longterm anthropogenic climate change impacts. These interactions have significant policy and economic implications, and must not be ignored in the climate policy discussions forum. As the climate negotiators are now shifting their focus towards reaching an agreement on appropriate stabilization targets and designing mitigation and adaptations strategies required to meet those targets, understanding and incorporating the highly important role of ocean as the most powerful climate change mitigator becomes of utmost importance.

LINKS & REFERENCE

https://science.sciencemag.org/content/360/6394/1189

https://news.rutgers.edu/climate-change-means-fish-are-moving-faster-fishing-rules-rutgers-led-study-says/20180612#.WypjrH8napr

http://science.sciencemag.org/lookup/doi/10.1126/science.aau1758

https://www.news.ucsb.edu/2019/019360/warm-seas-scatter-fish

http://oceanscientists.org/index.php/topics/ocean-warming

HOW MUCH IS THE EARTH HEATING UP - As of early 2017, the Earth had warmed by roughly 2 degrees Fahrenheit (more than 1 degree Celsius) since 1880, when records began at a global scale. The number may sound low, but as an average over the surface of an entire planet, it is actually high, which explains why much of the world’s land ice is starting to melt and the oceans are rising at an accelerating pace. If greenhouse gas emissions continue unchecked, scientists say, the global warming could ultimately exceed 8 degrees Fahrenheit, which would undermine the planet’s capacity to support a large human population.

ADRIATIC - ARCTIC - ATLANTIC - BALTIC - BAY BENGAL - BAY BISCAY - BERING - BLACK - CARIBBEAN - EAST CHINA SEA

ENGLISH CH - GUANABARA - GULF GUINEA - GULF MEXICO - INDIAN - IRC - MEDITERRANEAN - NORTH SEA - PACIFIC

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