Various Human Activities That Change Food Chains

Various Human Activities That change Food
chains
1. Agriculture
With the ever increasing number of the world’s population, there is similarly a soaring
demand for sufficient food. The population growth rate is hence driving the world to
clear forests in order to create more room for agriculture. Based on data by the UN
Food and Agriculture Organization (FAO), more than 40% of earth’s surface now
supports agriculture, and a bigger fraction of these lands were formerly covered by
forests.
 Destruction of wildlife: Forests are critical habitats for wildlife and as
ecosystems supporting the intricate relationship between living and non-
living things, they have been adversely affected by agricultural practices. A
larger percentage of Europe, for example, was densely covered with
temperate forests but with time it has been cleared to make room for farm
land.
 Global warming and climate change: Population growth-influenced
deforestation is to blame for three billion tons of CO2 released into the
atmosphere each year which is equivalent to the destruction of 13 million
hectares of land annually as put forward by Union of Concerned Scientists.
This rate of deforestation affects the ecosystem by raising global
temperatures and disrupting the cycle of condensation and evaporation.
Various ecosystems such as the Polar regions are in turn affected by the
rising global temperatures and changes in atmospheric water cycle.
 Aquatic resources degradation: The injection of vast amounts of
phosphorous and nitrogen nutrients into natural soils, lands and water
systems due to fertilizer use have created far-reaching effects, altered
ecosystems, and rapidly expanded aquatic dead zones.
2. Plastic production
The invention of plastic has created one of the most problematic pollution problem
ever witnessed on the face of earth. Waste plastic is everywhere on earth even in the
oceans. Plastics remain in the environment for thousands of years and have long-
lasting consequences on the fragile ecosystems and regulatory cycles.
Presently, the world produces nearly 300 million tons of plastics yearly and 20% to
40% of this winds up in the landfills with 10 to 20 million tons finding way into the
world’s oceans, interrupting aquatic life. Plastics floating in the world oceans are
estimated to amount to 5.2 trillion weighing a total of 268,940 tons based a research
study done by World Watch Institute.
The chemicals present in the plastics are released in the waters, interfering with
animals endocrine systems and changing their reproduction patterns. They can also
cause rapid cell division which may result in cancers. Above all, since the plastics
remain in the oceans for years and years, they can ultimately reverse ecosystems with
damage costs approximated at 13 billion US dollars in a year.
Wildlife is most affected and some have even died after consuming unusually great
amounts of plastics. A whale found dead in the coast of Scotland in June 2017, for
example, had consumed nine pounds of plastic causing blockage in its digestive tract.
To make the matters even worse, more than 4,000 cases of fish with plastics in their
bodies have been recorded worldwide.
3. Emission of Carbon Dioxide and other greenhouse

gases
The emission of carbon dioxide and other greenhouse gases namely methane and
hydrofluorocarbons (HFCs) are human induced through combustion of fossil fuels and
the use of man-made products. In a bid to generate energy, the world has continued
to depend on carbon-rich fossil fuels namely gas, oil and coal.
The combustion of these fossil fuels to produce energy in the years between 1870 and
2013 produced approximately 400 billion tons of carbon dioxide into the atmosphere.
Today, carbon dioxide levels are said to be surprisingly higher than ever in history. As
a result, global temperatures are in the rise contributing to sea level rise and extreme
weather events like heat waves, flooding, tsunamis, and droughts. The sea level rise
and extreme weather events have in turn altered ocean and land ecosystems,
impacted food chains and biodiversity, and intensified desertification.
4. Destruction of the reefs

Ocean reefs are the globe’s richest oceanic ecosystems but human activities have led
to their destruction by upsetting the natural flow of nutrients and energy that support
plant and animal species in the marine world. Water pollution, climate
change, overfishing and acidification of marine waters are the repercussions of
human activities that have caused the destruction of coral reefs.
Experts say that one-fifth of global reefs are already destroyed and one-fourth of reef
species might go extinct by 2050. Further, the livelihoods of about 500 million people
globally depend on the coral reefs for survival because these are the critical growth
and reproductive areas for many fish species.
The reefs simply provide shelter and productive grounds for aquatic species and upon
their degradation or destruction, they stop providing the essential materials for a
vibrant interconnectedness that is necessary for supporting specific aquatic
ecosystems. The reason for this is that the destroyed coral reefs are mainly
dominated by jellyfish and bacteria, which limits the capacity for sufficient regulation
of energy and nutrients.
5. Production of Black carbon

Black carbon particles have been generated by human activities for hundreds and
hundreds of years. Black carbon particles are materials emitted into the atmosphere
as smoke and are produced from cooking with solid animal fuels, burning firewood,
diesel car exhausts, and the burning of trees. The presence of these particles in the
atmosphere creates a heat-absorbing layer that gives rise to increased global
temperatures, thus compounding the global warming effect.
Nations heavily dependent on diesel fuel, coal, and burning of wood or cow dung fuel
for heating and cooking are the biggest emitters of black carbon. Black carbon has
also changed weather patterns and reduced rainfall in West Africa and south Asia
according to various science reports. It has also played a role in the melting of the
glaciers in the Himalayan region, threatening ecosystems and water supplies for
millions people.
6. Draining streams/rivers and destruction of critical

fresh water aquifer recharge areas
Various anthropogenic activities have heavily destroyed fresh water supplies such as
rivers, streams, and aquifers. Intensive agriculture is a leading cause on the account of
the large amounts of chemical fertilizers, herbicides and other agro-chemicals that
find way into waterways.
Intensive agriculture is also water intensive thus over-drains rivers and degrades
critical freshwater aquifer recharge areas. The construction of man-made dams and
water-diversion for irrigation or during infrastructural construction has also made the
natural flow of water in rivers and streams inefficient. As such, these practices have
gradually destroyed fresh water recharge capabilities, increased salt intrusion, and
changed local weather patterns in turn affecting local ecosystems such as forests,
lakes and wetlands.
Increased salt concentration in lakes has made it difficult for some fish species to
survive. Furthermore, most of the world’s lakes that supported a wide range of diverse
animal and plant species have shrunk by more than half of their original sizes just
because of over-draining rivers and the destruction of fresh water aquifers.
7. Overhunting and overexploitation

Overhunting and overexploitation of natural resources through activities
like overfishing and mining have caused a reduction in the number of varied plant and
animal species. In other words, the diverse existence of animal and plant species in
different habitats has been widely affected by overhunting and overexploitation.
These human activities do not give room for the replenishment, growth, or new
development of already exploited or harvested products.
Overhunting can cause extinction, destroy natural reserves and breading areas,
and affects food chains. Therefore, whenever any living thing or native species that
plays a part in an ecosystem is taken away in large quantities or becomes extinct, the
entire ecosystem suffers and can be permanently altered. Also, when humans convert
forests into farmlands or river basins into mining areas, the areas are made harsh for
the survival of animal and plant species.

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Various Human Activities That change Food

3. Emission of Carbon Dioxide and other greenhouse

4. Destruction of the reefs

5. Production of Black carbon

6. Draining streams/rivers and destruction of critical

7. Overhunting and overexploitation

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