Ecology And Environment
how climate change affects ecosystems

How Climate Change Affects Ecosystems

how climate change affects ecosystems
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"How Climate Change Affects Ecosystems"
Caption: how climate change affects ecosystems
Image by: national geographic
© national geographic

Ecosystems are plant and animal communities which live and thrive dependent on each other and the climate that supports them.   Climate change affects  ecosystems in ways that ecologists have been warning about for decades (since the late ‘60s to be exact) and even in ways they had not predicted.  It is taking place as this text is being written, from the Arctic to the Antarctic and from tropical rainforests to one’s own back yard. Generally, there is a trend in terrestrial species as well as flora and fauna to move northwards and to higher elevations. Due to a warmer climate there are earlier spring phenomena, migration and a lengthening of the growing season. Climate change is dictating which species will die out and which, whether they be detrimental to the planet or not, will thrive and multiply.


Due to the rise in temperature, mammals which normally hibernate quite often have trouble falling into hibernation. Several years ago in the area of Macedonia, Greece, the bears of the region had trouble hibernating and were experiencing an in-between stage.  As a result, several hypnotically wandered close to villages looking for food.   

In other parts of the world, hibernating mammals have migrated further north while others have experienced an increase in body size; due to a greater abundance of food owing to the changes in the climate. The polar bear is perhaps one of the mammals that is suffering the most.  It is dependent on sea ice to hunt seals and move from one area to another.  Not only has the animal’s reproduction declined as a result of the melting ice phenomenon, but many have also died of exhaustion while forced to swim in search of food.

A complete loss of summer sea-ice  is estimated to result sometime before the century ends. This would mean the end of the polar bear as well as the seals it hunts since they rely on the ice as well.  The seals give birth to their young on ice and use it as a resting area. Due to the rise in temperatures, tundra vegetation zones tend to shift further north. This in turn makes it highly likely for caribou and reindeer populations to decline since they are dependent on the tundra vegetation.

The greater importance of ice

Bright white ice reflects sunlight.

When there is no ice, the ocean and the air heat much faster. This accelerates the ice melting and the heating of surface air inland, with ensuing loss of tundra. 

“Less sea ice leads to changes in seawater temperature and salinity, leading to changes in primary productivity and species composition of plankton and fish, as well as large-scale changes in ocean circulation, affecting biodiversity well beyond the Arctic.”

— Secretariat of the Convention on Biological Diversity (2010), Global Biodiversity Outlook 3 May, 2010, p.57


Of all the animal species, 97% are invertebrates. Their influence on their surroundings exceeds their size. Their role in the cycle of life is quite significant as bees, moths, ants and other insects not only signify the survival of other animal species but that of plants as well. Predominantly vital in the production of certain fruits, nuts and vegetables is insect pollination.

The change in climate recently in Alaska caused spruce budworms (most destructive pests of coniferous trees in the western United States) to reproduce further north.  In the early ‘90s, another abrupt boom and spread of spruce bark beetles (also a serious insect pest) caused 10-20% mortality of trees in the Kenai Peninsula in south-central Alaska.  A further expansion of the Bark Beetles in the Western United States is expected due to climate change.  Moreover, butterfly habitats in North America have moved further to the north.  The Edith Checkerspot Butterfly, for instance, is no longer found in the southern portion of their habitat range.

Oceans Depleted of Life

Change has touched the ocean, the sky and the terrain.  It has not only affected how species survive but it has also brought about dead zones. Oceanic dead zones are areas very low in dissolved oxygen that cannot sustain life.  A 2009 study warned that the continuation of ocean warming would increase stratification and produce greater dead zone areas with a major impact on fish populations.  Ocean stratification is when warm water covers cold water (rich in nutrients) creating dead zones and lowering the productivity of the ocean. 

“It will take a thousand years for the oceans to cool down…” — Stephen Leahy, Ocean Losing Its Green, Inter Press Service, July 31, 2010

If everyone simply stopped and took a closer look at his/her surroundings, there would be a definite awareness of distinct differences between today and the past.  Such distinctions as subtle as are insects enduring all through winter that in the recent past would not have or a spring garden void of  its protector, the lady bug, ready to fend off any tiny pests feeding on beautiful blooming rose bushes and other plants.  And it is these subtle disparities that add up to shape the vast perils of this world. Perils incurred by man alone.

More about this author: Litsa Podaras

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