Posts Tagged global warming

Jun 4 2015

Global warming may cause largest ocean species migration in 3 million years

Giantshark

 

If greenhouse gas emissions are not curtailed soon, then global warming may bring about the most sweeping re-arrangement of ocean species in at least 3 million years, according to a new study.

The study, published Monday in the journal Nature Climate Change, shows that by the end of the century, the polar regions may be have some of the most abundant and diverse sea life of anywhere on the planet, while the tropics, which are currently the crown jewel of marine species richness, may be drained of much of its iconic marine life.

The stakes involved in which ocean species live where are high since, globally, we depend on proteins derived from fish, crustaceans and mollusks for up to a quarter of our animal protein intake, according to the World Health Organization. In 2010, fish provided more than 2.9 billion people with almost 20% of their intake of animal protein, according to the Marine Stewardship Council, and 4.3 billion people with about 15% of such protein. In some countries, these figures are higher.

The study, which attempts to quantify the shifts in biodiversity that may occur during this century throughout the global ocean, offers a stark warning ahead of global climate talks in Paris in December.

It finds that global warming may not alter the oceans in a profound way if emissions are cut sufficiently to meet the globally agreed upon temperature target of 2 degrees Celsius, or 3.6 degrees Fahrenheit, compared to preindustrial levels. Some policymakers now consider that goal to be nearly impossible, given the continued rise in planet-warming greenhouse gases such as carbon dioxide.

Emissions over next few years determine ocean’s destiny

If warming is held at the 2-degree target, says study co-author Richard Kirby, the changes that will occur throughout the global ocean “will be relatively benign for the ecosystem.” Kirby is affiliated with the Marine Biological Association in the U.K..

Study coauthor Grégory Beaugrand, a senior researcher at an ocean laboratory in Lille, France, and a consultant at the Sir Alister Hardy Foundation for Ocean Science in the U.K., says that tropical regions would see a net loss in biodiversity with average global warming of 2 degrees Celsius, while polar areas could see a 300% increase in biodiversity as species seek out more hospitable areas.

Tuna

A tuna fish swims in the large tank at the Tokyo Sea Life Park in Tokyo on March 25, 2015. Image: TOSHIFUMI KITAMURA/AFP/Getty Images

However, if emissions stay on their current, high path, then in just the span of one century, there could be a larger biodiversity shift than the global oceans saw since the mid-Pliocene period more than 3 million years ago.

This would be a staggering amount of change in such a short time period, which could result in many surprises that scientists don’t yet anticipate. It would also present unprecedented challenges for the fishing industry, which is locally adapted to catching present-day species, including the rapidly-growing global aquaculture industry.

As species migrate toward the poles, fishing fleets will have to be remodeled to hunt for a new mix of species. This has occurred already in Newfoundland and parts of the northeast U.S., where the cod fishery has collapsed, giving way to more of a lobster and crab fishery. This shift is not an easy one to make, since crab fishing requires totally different gear than hunting groundfish species like cod and haddock.

“The transition period will have a devastating impact on fisherman and from a socioeconomic point of view,” Beaugrand told Mashable.

Even a moderate warming that is less than a worst-case scenario could yield a major reorganization of marine biodiversity over large oceanic regions by the 2081-2100 period. These changes may be at least three times greater than the shifts observed between the years 1960-2013, the study found.

Exceeding the 2 degrees Celsius target, Beaugrand said in an interview, would mean that “between 78 and 95% of the ocean will show substantial changes” in biodiversity by the end of the century.

Species are already packing up and heading away from the equator

Unlike terrestrial species, marine creatures can and already are migrating in search of more suitable environments once temperatures exceed their tolerable ranges. This has been seen in several studies of the North Sea in particular, where shifts in the amount and types of plankton and other foraminifera as well as commercially-prized fish have been observed.

In the northeast Atlantic, for example, plankton, which are organisms that produce oxygen through photosynthesis and form the foundation of the marine food web, have already shifted northward by 10 degrees of latitude due in part to ocean temperature increases in that region.

Kirby says that people tend to forget that humans depend on temperature-sensitive organisms as tiny as plankton. “The rest of life on earth lives where the temperature suits it. If that changes, it moves, in sea it tends to move because it can,” he said. “It’s those movements, especially lower down in the food web, that underpin the whole marine food chain upon which we depend.”

Fishing in Somalia
Somalian fisherman carries swordfish on his head from the port to the fish market on the eastern Curubo beach of the Somalian capital city of Mogadishu, on November 24, 2014.

When looking at changes between 1960 and 2013, the study found that 30% of the area of ocean already showed substantial changes in biodiversity, “which is six times higher” than changes due to natural variability alone, Beaugrand said.

“Climate change already has an impact on marine biodiversity,” he says.

A severe global warming scenario featuring continued emissions growth through the end of the century could cause between 50 to 70% of the world’s oceans to experience a change in marine biodiversity comparable or more extensive that those that occurred since the mid-Pliocene and today, as well as since the last glacial maximum — when thick ice sheets covered areas from Washington, D.C., to Seattle and northward.

“It’s really worrying, because this is the whole ocean that will change,” Beaugrand says.

The mid-Pliocene is of interest because it was the last time that climate conditions are thought to have been similar to what is projected for the end of the century. At that time, global carbon dioxide concentrations were about 400 parts per million, which is where it stands now, and global average temperatures were 2 to 3 degrees Celsius (3.6 to 5.4 degrees Fahrenheit) higher than today. Global sea levels were about 66 feet higher than today, as well.

India Daily Life

An Indian fisherman cleans fish in the river Brahmaputra in Gauhati, Assam state, India, Sunday, April 19, 2015. Image: Anupam Nath/Associated Press

The last glacial maximum lasted from about 26,500 to 20,000 years ago. During this time period, the amount of carbon dioxide in the air was just 190 parts per million, according to the study, and the average sea level was 425 feet below current levels.

Between the last glacial maximum and today, about 85% of the global ocean area showed substantial modification in marine biodiversity, Beaugrand said, while between the mid-Pliocene and today, 75% of the global ocean showed substantial changes. Yet this all played out over thousands to millions of years, not in just a century, which is the timeline we’re looking at with regards to manmade global warming.

In other words, there’s no precedent in all of human history for what may be about to happen, which is extraordinarily risky given that we depend on the oceans for ecosystem services from food to oxygen production and heat storage.

Generating ‘pseudo species’

The study used a theoretical model that relies upon fundamental ecological principles and previously known findings of how biodiversity changes with temperature fluctuations to come up with, essentially, “pseudo marine communities,” as the study refers to them. The authors compared the modeled biodiversity patterns to observed patterns based on previous studies, and found that there was a statistically significant amount of agreement.

The study allowed tens of thousands of modeled species, each with different biological properties including temperature ranges, to colonize the ocean. The researchers used data from deep sea sediment cores to look at how plankton groups have changed through time in order to fine-tune their modeling results.

One drawback to this study, as well as others that focus on global ocean species, is that we know more about Mars than we do about much of the ocean. So far, Beaugrand says, we’ve only described the characteristics of about 200,000 marine species, which is about 10% of the marine biodiversity that scientists think is out there. We have an incomplete knowledge of marine biology and spatial distribution — that could limit the reliability of studies like this to some extent.

Another wild card is exactly how ocean acidification, which is also caused by climate change, will alter marine biodiversity and functioning of marine ecosystems. Such studies are currently in their infancy.


Read the original post: www.mashable.com

 

Jan 5 2013

El Niños Are Highly Unpredictable

El Niño events are not as predictable as scientists thought. The frequency and strength of the ocean-warming climate phenomenon

It’s in there. Corals collected on islands in the central Pacific reveal that the strength and frequency of the climate phenomenon commonly known as El Niño is highly unpredictable.
Credit: Gary Meek/Georgia Tech

were more variable during the 20th century than, on average, during the preceding 7000 years, according to new analyses of climate records locked within ancient corals. The finding largely discounts the idea that certain long-term variations in Earth’s orbit strongly influence the climate-maker, scientists say.

“This will be a shock for many paleoclimatologists,” says Axel Timmermann, a climate scientist at the University of Hawaii, Manoa, in Honolulu who wasn’t involved in the new research. “[These findings] are a stark contrast to their ideas.”

El Niños are marked by substantially warmer-than-normal sea-surface temperatures along the equatorial Pacific. These events—along with their alter egos La Niñas, which are defined by cooler-than-average sea-surface temperatures in the same region—steer weather patterns across large swaths of the globe, baking some areas while drowning others. Together, these phenomena are called the El Niño-Southern Oscillation (ENSO). In modern times, El Niños occur once every 2 to 7 years; sometimes they’re strong and long-lasting, and other times they’re brief and mild.

Read the full article here.

 

Nov 7 2012

Hurricane Sandy, Climate Change, and the Future of Fish

Brian Hajeski, 41, of Brick, New Jersey, reacts as he looks at debris of a home that washed up on to the Mantoloking Bridge the morning after Hurricane Sandy rolled through, Tuesday, October 30, 2012, in Mantoloking, New Jersey.

Hurricane Sandy’s terrible toll in lost lives and decimated communities is still being measured. But as we start to sort out the pieces, it’s also worth noting that the storm sent shockwaves through the mid-Atlantic region’s fishing industry. Harbors and infrastructure were pummeled and in some cases destroyed along the New York and New Jersey coastlines, and the Garden State Seafood Association has already asked Gov. Chris Christie (R-NJ) to formally request a federal fisheries disaster declaration.

In the aftermath of the storm, the link between our changing climate and increasingly extreme weather is coming into greater focus and being called out by an increasingly large caucus. (For more on the link between climate and extreme weather events in North America, see this new column by the Center for American Progress.) New York Gov. Andrew Cuomo was among the first to link Sandy’s fury to the “reality” of climate change. Bloomberg Businessweek ran a cover story under the banner headline, “It’s Global Warming, Stupid,” which called out the increasing spate of corporate voices accounting for climate change in their business models. And the magazine’s namesake, New York Mayor Michael Bloomberg, cited climate change as the tipping point that led to his much-ballyhooed endorsement of President Barack Obama for reelection.

Click here to read the full article.

 

Sep 14 2012

Sea Level’s Rise Focus of Summit

Projections of dramatic change draw group to UCSD to strategize about vulnerabilities of affected areas

LA JOLLA — Climate researchers, social scientists and policy experts from across the Pacific Rim convened at UC San Diego last week to get ahead of seas projected to rise so dramatically that they could create some of the most visible effects of global warming.

Representatives from about 20 leading research universities and nonprofit groups in South Korea, Russia, Indonesia and elsewhere met to prepare for potentially catastrophic effects on 200 million people and trillions of dollars of coastal assets.

Sea levels off most of California are expected to rise about 3 feet by 2100, according to recent projections by the National Research Council. Higher seas create challenges for port cities from San Diego to Singapore, including the potential for dramatically increased damage to coastal roads, homes and beaches — especially during storms.

“All future development has to be assessed in regards to future rises in sea level,” Steffen Lehmann, professor of sustainable design at the University of South Australia, said during the conference. “Reducing the vulnerabilities of urban (areas) is the big topic, the big task ahead of us now.”

Potential responses include managing a retreat from eroding bluffs and reshaping coastal areas to buffer development from higher water levels. “The missing link (is) between the science and those guys in planning offices and architecture firms and city municipal offices,” Lehmann said.

David Woodruff, director of the University of California San Diego’s Sustainability Solutions Institute, organized the workshop to address that problem with cross-disciplinary discussions that move toward international action.

“We are trying to affect societal change,” he said. “The sooner we start scoping options, the less expensive it will be to save current infrastructure.”

The workshop was sponsored by the Association of Pacific Rim Universities, a consortium of 42 leading research institutions. Participants drafted a report about rising sea levels for top university leaders so they can make the topic a priority with national-level leaders around the Pacific Rim.

“I really think universities can play a key role,” said UC San Diego’s Charles Kennel. “They are right at the pivot point between connecting knowledge to action. … One of the places they need to transfer their knowledge to is adaptation to climate change.”

A warming climate causes sea levels to rise primarily by heating the oceans — which causes the water to expand — and by melting land ice, which drains water to the ocean. Sea levels at any given spot depend on a complex interaction of factors, such as ocean and atmospheric circulation patterns and tectonic plate movements.

Global sea level has risen about 7 inches during the 20th century, the National Research Council said.

While sea-level-rise projections aren’t a sure thing, they are widely accepted by mainstream scientists. Skeptics see it as a waste of money to plan for problems that may not materialize for decades, or may be more modest than predicted.

Read more on the Union-Tribune San Diego.

 
Mar 9 2011

Shifting spring: Arctic plankton blooming up to 50 days earlier now

By Brian Vastag
Washington Post Staff Writer

A light micrograph of plankton including water fleas (family Daphniidae) (Getty Images/oxford Scientific)

Climate researchers have long warned that the Arctic is particularly vulnerable to global warming. The dramatic shrinking of sea ice in areas circling the North Pole highlights those concerns.

A new report finds that the disappearing ice has apparently triggered another dramatic event – one that could disrupt the entire ecosystem of fish, shellfish, birds, and marine mammals that thrive in the harsh northern climate.

Each summer, an explosion of tiny ocean-dwelling plants and algae, called phytoplankton, anchors the Arctic food web.

But these vital annual blooms of phytoplankton are now peaking up to 50 days earlier than they did just 14 years ago, satellite data show.

“The ice is retreating earlier in the Arctic, and the phytoplankton blooms are also starting earlier,” said study leader Mati Kahru, an oceanographer at the Scripps Institution of Oceanography in San Diego.

Read the rest of the story here.