RISING SEAS
One of
the most beautiful things on this earth are the oceans, which occupy a large
expanse of it! As Indians, we all are proud of our northern protective mountain
ranges of Himalayas, which feed seven of
Asia’s large and majestic rivers; Ganga, Indus, Brahmaputra, Salween, Mekong,
Yangtze and Huang He. Himalayas stand tall with their majestic landscape, rightly
known as the ‘Water Towers of Asia’. instilling a sense of awe, wonder and
amazement, spanning about 33,000 kms of glaciers. During summer, Himalayas are
an important source of water for huge human population. Himalayas are presently
facing the effects of climate changes and undesirable human activities and glaciers
are retreating. Glaciers contribute up to 75 per cent of river water during
summers and their retreat leads to freshwater scarcity during dry seasons, affecting
regional agriculture and energy sources. Loss of melting water of glaciers
affects downstream water flows, affecting the lives of several million Indians.
Globally too, this has a large impact!
Since 1880, global average sea level
has increased 8 inches, about 7 cms over the last 22 years, due to global,
regional, and local factors.
·
Along the East Coast and Gulf of Mexico,
path changes and strength of ocean currents have led to fast sea level rise.
·
In East Coast and Gulf regions,
subsiding land has led to ocean penetrating inland.
·
Shrinking of glaciers, land ice, ice
caps and sheets has speeded up.
·
Loss of land ice has added about half inch
to global sea level during 2003 to 2007, leading to 75 to 80 per cent of the
increase.
·
The long-term global sea level rise depends
on heat-trapping emissions and quick response
of land ice to increasing temperatures.
·
Past heat-trapping emissions of gases
will affect rise in sea level up to 2050, present and future emissions will affect
it after 2050.
·
We have already affected the environment
so badly that even if emissions drop to nil, sea levels will keep rising as
oceans and land ice need to adjust to the undesirable changes.
·
The greatest impact will be on rate and
magnitude of the loss of ice sheets, in Antarctic regions, due to the
atmospheric heat-trapping emissions.
Changing sea levels are due to different reasons, but climate
change is the driving
force! 2 degree rise in temperature would lead to sea rise by 0.4 to 1.4 meters due to thermal
expansion. Melting ice sheets add to the total amount of water in the world’s
oceans, predicting a sea rise by 19 to 59 cm by 2100.
As the earth heats, sea
water warms up taking up more space causing thermal expansion. Melting glaciers
and ice sheets add even more water into the oceans, leading to a rise in sea
level.
In winter, snows balance melting. Today, global
warming has resulted in continuously elevated temperatures causing above average
melting, less snowfall causing imbalance and rise in sea levels.
Massive ice shelves are weakening and breaking
off because of melting. Increase in ocean's mass leads to a global sea
level rise of 1.9 mms each At this rate, 6.4 meters sea level rise may be
expected in upcoming years. Irreversible melting already occurred may require hundreds
of years to reverse.
Rising sea levels lead to;
·
Higher risks of erosion and floods,
·
Damage to manmade infrastructures,
·
Disturbing of delicate coastal ecosystems
·
Rising sea water contaminates agricultural land
·
Rising sea water contaminates drinking water.
·
Erodes shorelines
·
Causes loss of wetland
·
Allows salt water to enter fresh water bodies
·
On
penetrating inland, it may lead to destructive erosion
·
Flooding of
wetlands
·
Contamination
of aquifers and agricultural soils,
·
Disturb habitat
for fish, birds, plants.
·
Large storms
can submerge low-lying islands
·
Coastal areas may be disproportionately affected
due to ocean currents.
·
This may disturb homes and livelihoods of people
in coastal areas of the globe.
SOLUTIONS:
·
Burn no or fewer
fossil fuels.
·
Curb
emissions of certain pollutants
·
Reduce emissions
of methane, tropospheric ozone, hydro fluorocarbons and black carbon, specific
pollutants which may prevent rise in sea level by about 25 to 50 per cent.
·
Cut back on
motor vehicle exhaust
·
Curb industrial
emissions, chemical solvents, windshield washer fluid, create fewer CFCs
·
Cut back on
smoke or soot generating activities.
Many countries have managed rising sea levels by;
·
Construction of sea defences such as dams and
other barriers.
·
Coastal armouring is used to raise and fix
shorelines in place, through seawalls or levees. Infrastructure could be
designed to be elevated or buoyant to deal with rising waters.
·
Developing and nurturing coastal biomes is a
good protection against rising sea water. Ecosystems such as wetlands and
mangrove forests protect shorelines from erosion.
In vulnerable areas, well-managed migrations and
early-warning flood systems are needed to help people threatened by rising sea
levels.
Over the long term, scientists warn that the only way to
limit sea level rise
will be to drastically reduce emissions of the greenhouse gases dangerously warming the planet, though already significant irreversible damage has been
done.
We tend to
attribute all this to "climate change", which is deceptive! We should
now pledge to stop using the term “climate change” and start using the words increasing global warming or disturbed climate to describe the destruction caused by global warming
primarily due to human activities like burning of fossil fuels.
The choices we make today, the life
style we adopt today, the habits we inculcate in ourselves today, will
determine how the sea level rises this century, how fast it occurs and how much
time we really get to protect our communities!
Dr. Mrs. Jaya Vikas Kurhekar,
Green Blogger
