| Dear
EarthTalk: If the ice caps are melting, what is happening
to the salt content of the oceans? And might this contribute
to weather patterns or cause other environmental problems?
-- George Boyer,
via e-mail
| |
The
melting of the polar ice caps is sending large amounts
of fresh water into the world‘s oceans. Many
climate scientists fear that if the climate heats
up fast enough and melts off the remaining polar ice
rapidly, the influx of fresh water could stall out
the Gulf Stream and rob the northeastern U.S. and
northwestern Europe of their natural heating source,
plunging the two continents into a cold snap that
could last decades or longer.
© Getty Images |
It‘s
true that the melting of the polar ice caps as a result
of global warming is sending large amounts of freshwater
into the world’s oceans. Environmentalists and many
climate scientists fear that if the climate heats up fast
enough and melts off the remaining polar ice rapidly, the
influx of freshwater could disturb ocean currents enough
to drastically change the weather on the land as well.
The Gulf Stream,
a ribbon of ocean water that delivers heat from the tropics
up to the North Atlantic, keeps northeastern U.S. and northwestern
Europe weather much milder than other areas at the same
latitude around the globe. In theory, less salt in the ocean
could stall out the Gulf Stream and rob some of the world’s
greatest civilization centers of their natural heating source,
plunging the two continents into a cold snap that could
last decades or longer—even as the rest of the globe
warms around them.
The Gulf Stream
keeps running because the warmer water travelling north
is lighter than cold water, so it floats on top and keeps
moving. As the current approaches the northern Atlantic
and disgorges its heat, it grows denser and sinks, at which
point it flows back to the south, crossing under the northbound
Gulf Stream, until it reaches the tropics to start the cycle
all over again. This cycle has allowed humans and other
life forms to thrive across wide swaths of formerly frozen
continents over thousands of years. But if too much dilution
occurs, the water will get lighter, idling on top and stalling
out the system.
Some scientists
worry that this grim future is fast approaching. Researchers
from Britain‘s National Oceanography Center have noticed
a marked slowing in the Gulf Stream since the late 1950s.
They suspect that the increased release of Arctic and Greenland
meltwater is to blame for overwhelming the cycle, and fear
that more warming could plunge temperatures significantly
lower across land masses known as some of the most hospitable
places for humans to live.
Of course—not
surprisingly—others have noted a contradictory trend:
Some parts of the world’s oceans are getting saltier.
Researchers from the UK‘s Met Office and Reading University
reported in a recent issue of the peer-reviewed journal
Geophysical Research Letters that warmer temperatures over
southerly sections of the Atlantic Ocean have significantly
increased evaporation and reduced rainfall from Africa to
the Caribbean in recent years, concentrating salt in the
water that’s left behind. In fact, the Atlantic in
this region is about 0.5 percent saltier than it was four
decades ago.
But given how
little we really know about the future effects of our carbon
loading of the atmosphere, calling these two trends contradictory
might be premature—as the two regions of ocean interact
with one another and are part of a larger whole. Looking
instead at the big picture, it’s clear that climate
change is already having a relatively large effect on the
world’s oceans by fundamentally altering evaporation
and precipitation cycles. Only time will tell how dramatic
the results of these changes will be.
CONTACTS:
National
Oceanography Center; Met
Office; Geophysical
Research Letters.
Dear EarthTalk:
Where do I recycle old ski boots (hard plastic)?
My recycling center does not take hard plastic.
-- Beth Fitzpatrick,
Stamford, CT
| |
Americans
recycle more plastic than ever these days, but there
are still plenty of items that are not accepted by
municipalities, including many hard plastic items
like ski boots.
© Getty Images |
Americans recycle
more plastic than ever these days, but there are still plenty
of items that are not accepted by municipalities, including
many hard plastic items like ski boots.
If such items
are still usable, consider donating them to a local Goodwill
or Salvation Army store, which can sell them and put the
money earned toward housing and feeding those less fortunate.
Another option would be to sell or give them to a second-hand
sporting goods store, which might even give you trade-in
credit toward an upgrade. If you can’t find somewhere
local, you can ship them to Colorado-based Boulder Ski Deals.
The company accepts ski boots (along with skis, bindings,
poles and snowboards) for recycling, donating usable equipment
to charitable programs and shredding the rest for re-use
in making new products.
The fact that
it is so difficult to recycle hard plastic items is a growing
issue as we all try to minimize our impact on the environment.
Everyone involved with the lifecycle of a given item—from
manufacturer to retailer to consumer—can share the
blame when something ends up taking up precious space in
a landfill instead of being recycled in one way or another.
Concerned consumers should make sure that a given item is
easy to recycle when its usefulness runs its course before
buying it in the first place. It also can’t hurt to
let a manufacturer know that you didn’t purchase a
given product because it didn’t meet your recyclability
standards. Manufacturers want to make products that people
will buy and such feedback can go a long way to getting
them to re-think their practices.
Likewise, municipalities
need to hear from residents if there is a need to expand
the types of items accepted for recycling. If enough people
are willing to recycle a certain type of item, it may be
worthwhile for the municipality to expand capacity and move
into new markets.
The good news
is that there are plenty of firms that are happy to take
back otherwise difficult-to-recycle stuff. The non-profit
Earth911 offers up a free searchable online database of
different types of recyclers keyed to the user‘s zip
code anywhere across the United States. If no local provider
comes up, the site will refer users to a place that accepts
shipped items. Another good resource is the consulting firm
Eco-Officiency‘s concise yet comprehensive online list
of companies around the country that accept different types
of hard plastic and other hard-to-recycle items.
Consumers should
keep in mind that they may have to pay for the privilege
of recycling certain items, as well as shipping costs. If
you can swing it, think of it as a tax for buying something
less friendly to the environment. Maybe next time you’ll
look for one made out of easier-to-recycle materials.
CONTACTS:
Boulder
Ski Deals; Earth911;
Eco-Officiency’s
Recycling and Donation Resources. |
