Human Population, The Root of Earth’s Problems?
Since the beginning of the industrial revolution the
human population has been growing at an alarming rate. The human population has
been growing exponentially along the same guidelines as any other species with
all of their food and shelter needs met. In fact our population growth can be
calculated using the same exponential growth models used to estimate unhindered
bacterial growth, with the only difference being the time scale for reproduction.
On the other hand the Population Reference Bureau explains how our population
has not been growing linearly as many once thought but instead it is growing
“arithmetically” meaning instead of doubling in a set amount of time repeatedly,
it doubled the first time, quadrupled the second, scaled by 8 the third, and so
on, (1). While the exact model of our exponential growth is somewhat debated
and unclear, the impact of this growth is not. Life requires resources and
every individual of the current 7.1 billion human population needs at least
food and shelter. The drive for the basic necessities pushes us to consume and
alter much of the natural ecosystems that once thrived in a perfect balance
before the human population explosion of the last few centuries. We are now
exploiting these ecosystems for all they’re worth and converting them to
agricultural and industrial regions that no longer resemble the lushes green
landscape Earth had been able to support for hundreds of millions of years.
Agriculture is at the heart of current deforestation
problems with a high percentage due to cattle ranching. In the graph above you
can see a breakdown of the percentage contribution of various human activities
leading to deforestation in the Brazilian Amazon. It is interesting that the
activities for providing shelter, like logging, represent such a small
percentage of the deforestation. Even small and large scale agriculture combined
doesn’t come close to the huge impact of cattle ranching. According to the
Netherlands Environmental Assessment Agency (NEAA) livestock is responsible for
roughly 80% of global land use for agriculture. Beyond that the NEAA found that
through land use and nitrogen emission from cattle, livestock is responsible
for as much as 30% of global biodiversity loss. This seemed surprising at first
but really shows the substantial difference in efficiency of eating plants, the
primary producers, compared to eating the primary consumers, cattle. Consumers
use a significant percentage of the food energy they eat for maintaining their
body functions which is not available as energy for the next and higher trophic
levels. Studies have shown that meat-based diets require much more energy,
land, and water resources than a vegetarian diet of the same calorie content,
(7). This shows some promise for being able to increase the efficiency of
agriculture and food supply around the world to support our population if we
switch to eating more primary producers and fewer cattle. However, if we can’t
manage to increase our agriculture efficiency we will see more and more
ecosystems destroyed to support our growing population.
We are facing an exponentially growing population that
has passed the level of natural sustainability more than 3 times over. It is
estimated that Earth can naturally sustain about 2 billion humans at a European
standard of living, (4). With such an extreme gap between our current
population and what we estimate the Earth can support sustainably we have been
forced to turn to unnatural means of food production including genetically
modified organisms or GM foods. As you can see in the chart above in just the
last decade the percentage of staple food products like corn and soybean that
are genetically modified has increased substantially reaching 80-90%. This is
true of other food products as well like canola and potatoes reaching 74%, (5).
While GM foods have increased the efficiency of producing primary foods and
allowed us to support an ever growing population there are many controversies
and environmental issues surrounding these foods. The science of genetic
manipulation is still in its infancy compared to other fields which leads many
to question if we can understand the possible negative effects of GM foods
before it is too late.
While developing more efficient methods of agriculture
and reducing the impact of cattle farming by eating less meat may help prevent
further deforestation and subsequent biodiversity loss, we need to look to the
root of the problem. Decreasing the impact of our actions is only part of the solution;
the other part needs to come from managing our population growth. Policies made
by governments on the number of children that couples are allowed to birth have
proved successful but very unpopular and sometimes inhumane. For example China’s
one child policy and other encouraging incentives successfully reduced the
fertility rate from 2.9 in 1979 to 1.7 by 1995 where it leveled and very slowly
declined to the present 1.6. It has been estimated that some 300 million births
were prevented which allowed for a higher quality of life for the current
population, (3). While this approach to population control was successful it
has been controversial as well, with reports of inhumane actions to having additional
children. Other countries have been successful in reducing their population
growth without strict rules. Iran instituted mandatory contraceptive courses
for couples applying for a marriage license which has resulted in smaller
family sizes. The United States has been able to follow a similar reduction in
fertility rates as China, 2.49 in 1970 to 1.89 current, with the help of Title
X of the Public Health Service Act in 1970. This act set aside funds for
reproductive education and contraceptive programs which significantly reduced
the number of unplanned pregnancies, (8). With a similar reduction in fertility
rates between more extreme methods and conservative approaches there is hope
for preventing further growth through education and making contraceptives available
to the public.
Our growing population is forcing us to alter the
planet more and more to survive. While we consider issues of deforestation,
climate change, and biodiversity loss every day we need to realize the
unsustainable population is the root of almost all of these problems and they
will only continue to get worse if we can’t stop it. We have turned to using
potentially harmful GM foods and other short term solutions to try to increase
efficiency and support our population. This has allowed us to continue
surviving past the Earth’s natural sustainable level for human population and
allowed many people to continue to ignore the main problem. If we are to save
the Earth and the billions of different species that co-exist with us we have
to direct our thoughts away from the secondary issues caused by our population
and attack the root cause of the problem. The biggest issue is getting people
talking about our population problem and realizing our responsibility to change
the future for the better. Making education and contraceptives available seems
like the most promising conservative and humane method of limited our growth.
This method has been shown to work in certain countries and should work on a
global scale if we can implement it soon before Earth is irreversibly altered
and life as we know it is no longer possible.
References
- Human Population: Population Growth: Teacher's Guide. Population Reference Bureau. N.p., n.d. Web. 15 May 2013. <http://www.prb.org/Educators/TeachersGuides/HumanPopulation/PopulationGrowth/TeachersGuide.aspx>.
- Deforestation in the Amazon. N.p., n.d. Web. 23 May 2013. <http://www.mongabay.com/brazil.html>.
- Therese Hesketh, Zhu Wei Xing. The Effect of China’s One Child Family Policy after 25 Years. N Eng J Med. September 2005;353:1171-1176.
- World Population Balance. N.p., n.d. Web. 26 May 2013 <http://www.worldpopulationbalance.org/3_times_sustainable>.
- Genetically Modified Foods: Harmful or Helpful? N.p., n.d. Web. 26 May 2013. <http://www.csa.com/discoveryguides/gmfood/overview.php>.
- David Pimental, Marcia Pimental. Sustainability of meat-based and plant-based diets and the environment. Am J Clin Nutr. September 2003; vol. 78 no. 3 660S-663S
- Westhoek, Henk. "The Impact of Livestock on Biodiversity." Netherlands Environmental Assessment Agency, n.d. Web.
- Sunsan A Cohen. The Numbers Tell the Story: The Reach and Impact of Title X. Guttmacher Ins. 2011; vol. 14 no.2
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