June 8 is World Oceans Day
|On this Day of the Oceans, let us -
- Change the way we look at oceans -what the sea means to us, and what it can give.
- Use the opportunity to learn more about the oceans - many of us do not realize the profusion of diverse and beautiful creatures and habitats that are found in oceans, and how our actions affect them.
- Do something positive for the oceans - by finding ways we can alter our daily lives to conserve the oceans and reduce the our impacts on its fragile ecosystems
|The Ocean Project, of which GDRC is a member, coordinated efforts with the World Ocean Network to celebrate the 13th Annual World Ocean Day (WOD), on June 8. WOD provides the opportunity to evaluate perspective, learn about ocean creatures and habitats, and ways to become a caretaker. Celebrate World Ocean Day by organizing or participating in activities that celebrate our world ocean that connects us all. Check The Ocean Project site for a list of ways your organization can celebrate World Ocean Day (WOD).
The world's oceans cover more than 70% of our planet's surface and the rich web of life
they support is the result of hundreds of millions of years of evolution. Nomadic
peoples were collecting shellfish and harvesting fish long before the dawn of settled
agriculture. Great human civilizations, from the Egyptians to the Polynesians relied on
the sea for commerce and transport, and now, at the end of the Twentieth Century, our
fate is as tied to the oceans as ever. We still rely on fish for a significant portion of our
daily protein needs, and more than $500 billion of the world's economy is tied to
ocean-based industries such as coastal tourism and shipping. Perhaps most important,
this vast mass of water acts to help regulate the global climate and to ensure that a
constant flow of vital nutrients is cycled throughout the biosphere.
But all is not well in the sea. Increased pressures from
overfishing, habitat destruction, pollution and the introduction
of invasive alien species have combined in recent decades to
threaten the diversity of life in estuaries, coastal waters and
oceans. Now a new threat, global warming, is making itself
felt, and its impacts could be devastating for life in the sea.
There can be no doubt that our world is getting warmer. 1998
was the hottest year since accurate records began in the 1840s,
and ten of the hottest years have occurred during the last 15
years. By examining growth rings from trees and ice cores
drilled in Antarctica, scientists have determined that the past
decade was the warmest in more than four centuries, and that the current rate of
warming is probably unprecedented in at least 10,000 years. In 1992, the more than
2500 scientists comprising the Intergovernmental Panel on Climate Change concluded
that the warming is caused at least in part by emissions of greenhouse gases from fossil
fuel use. As the world warms, the outlook for marine wildlife looks bleak unless we can
turn down the heat by reducing concentrations of the main greenhouse gas, carbon
dioxide, in the atmosphere.
- Sea-level Rise
One of the most talked about problems associated with climate change is sea-level rise.
Rising oceans could flood many millions of hectares of valuable coastal ecosystems
world-wide, from the shorebird havens of northern Europe's Waddensea and South
America's Suriname, to the highly populated river deltas of China, Vietnam and
Bangladesh, where millions of people live and depend on coastal fisheries. Sea-level rise
threatens whole nations on the low-lying coral atolls of the Pacific and Indian Oceans
and is already flooding valuable wetlands in America's Chesapeake Bay and Louisiana's
- Ocean Circulation
The havoc global warming could wreak on ocean life may be
much greater than we have previously imagined. The water in
the oceans circulates slowly around the world, driven by a
complex system of currents. Wind and the rotation of the
Earth are important in determining the flow of surface currents
and local areas of upwelling and downwelling, but the true
driving force of deep water movement is thermohaline
circulation. Sometimes called the ocean conveyer belt, this
mechanism is responsible for bringing the oxygen that sustains
life to the deepest reaches of the sea, and in moving warmer
waters from the tropics towards the poles. Movement of this
conveyer belt depends on sinking of cold water in certain polar regions, thereby
triggering the global thermohaline circulation. Global warming could alter this. Because
freshwater is less dense than seawater, increased precipitation, melting of polar glaciers
and ice caps could block the system by reducing the amount of cold water that sinks
downwards. The consequences of shutting down the conveyer belt would be
devastating for marine life.
- Polar Impacts
Signs of global warming are being observed throughout the ocean realm. The most
obvious changes are in the regions near the poles, where the warming has already been,
and will continue to be, greatest. The ice-edge is retreating in the Antarctic, and
scientists worry about irreversible changes, as happened when a huge portion of the
Larsen ice shelf collapsed in 1995 and large areas of two more ice sheets shattered into
the sea in 1999. Arctic ice masses appear to be thinning noticeably and seasonal ice is
forming later and melting earlier. Scientific data is backed up by the first-hand
observations of native Yupik and other indigenous communities in the Arctic. They
report that changes in ice conditions are making it dangerous to hunt in the Spring, and
that species dependent on sea ice, such as walrus, seals and polar bears are already
suffering. Global warming may threaten a whole way of life for these subsistence
communities. Other alarming signs of warming in 1997 and 1998 in the Arctic were
never-before seen blooms of marine algae so massive that they were easily visible from
space. In the Antarctic, declines in Adélie penguin and crabeater seal populations have
been linked to altered snow and ice conditions, and warming has also been linked to
reduced numbers of krill.
- Coral Reefs
In the tropics, global warming may be
precipitating a new crisis for coral reefs. Marine biologists note that 1997 and 1998
saw the worst episode of coral bleaching on record. Reports of bleaching due to high
sea temperatures came in from all over the world, with more than 30 nations reporting
losses in their reefs. Almost all species were affected, and the Indian Ocean was
particularly badly hit, with more than 90% of coral dying in some areas. While currently, there is no direct scientific evidence to suggest global warming is threathening corals, the high
temperatures in 1997 and 1998 were attributed to an unusually severe El Nino event,
and signal the types of changes we can expect as temperatures continue to climb.
New evidence suggests that even the
increased levels of carbon dioxide in the atmosphere may be harmful for reefs as it
weakens corals' calcium carbonate skeletons and makes them more susceptible to storm
damage and other erosion. Mobile-gear fishing is clearly a bigger threat, particularly in the case of deep sea corals. Coral reefs are home to an extraordinarily rich array of
marine life and provide vital resources to the tourism and fishing industries.
- Seabirds and invertebrates
Global warming is expected to decrease ocean productivity. We may be seeing this
effect already: zooplankton in the California Current have decreased more than 70%
since the 1950s, and may explain dramatic declines in seabirds like sooty shearwaters
and Cassin's auklets in recent years. Shearwaters and other seabirds off Alaska
including common murres died from starvation by the tens of thousands in the
exceptionally warm years of 1997 and 1998. Other species have been starting to change
their range in response to warming. Studies by scientists at Monterey Bay indicate that
species like anemones and crabs from the intertidal rock pools of the California coast
may be shifting their distribution in response to warming. Southern species have
increased in abundance and northern species have declined over the past 60 years as
waters have warmed. Similar changes have been recorded for the English Channel.
- Increasing Threats to Salmon
Among the most alarming recent changes has been the crash in populations of some
north Pacific salmon populations in the unusually warm years of 1997 and 1998.
Canadian scientists have shown that sockeye salmon are extremely sensitive to changes
in water temperature, particularly in the winter. Other species, including steelhead,
chum, and coho are similarly sensitive to water temperature. The warmer it gets, the
more food salmon need to survive. Eventually they reach a temperature threshold and
simply starve to death. Scientists predict that around the middle of the next century
there may be no marine habitat cool enough for salmon in the surface waters of the
Pacific. They will either have to migrate halfway up the Bering Sea, or learn to live
deeper in the water column. If neither happens, they may simply go extinct.
The startling changes already beginning to affect marine life may turn out to be merely
the tip of iceberg. Global warming is predicted to worsen rapidly, with average annual
temperatures expected to increase by about 3 degrees C by the middle of the next
century. Changes of this speed and magnitude could set off a chain reaction in marine
ecosystems with truly appalling consequences for life in the sea and for human
communities that depend on it. However, if we act now to reduce carbon pollution
from the dirtiest power stations and from vehicle exhausts, we stand a good chance of
slowing the warming and helping to save a healthy ocean for future generations.
- WWF (1999) Global Warming: The Oceans in Peril.World Wildlife Fund
(WWF) and Marine Conservation Biology Institute (MCBI)