Global Warming: Causes and Consequences


Global warming is widely considered to be the most important environmental issue affecting the world in the 21st century. There is unanimous agreement among scientists that global warming is happening. Reliable evidence supports the notion that global surface temperatures have increased by about 0.6oC over the past century (Degelman, 2002). Global warming leads to a number of severe environmental effects. For this reason, there have been calls by scientists for the issue to be actively addressed. A good understanding of what global warming is would be necessary for one to appreciate the impact of this event. This paper will define global warming, highlight its causes, impacts, and the measures that can be taken to mitigate it.

What is Global Warming?

Haldar (2010) defines global warming as “the increase in the average temperature of Earth’s near-surface air and oceans” (p.1). The mechanics of global warming can be explained by looking at the manner in which the earth’s lower atmosphere is heated by the sun. The radiation heat from the sun reaches the earth surface and it is reflected upwards as infrared heat. The infrared heat is trapped into the earth’s atmosphere by greenhouse gases.

These gases are essential for life on earth since without them, the infrared heat would escape the earth’s atmosphere causing the average temperature on earth to be -18oC instead of the present 14oC. Without greenhouse gases, the earth would lose most of its heat at night when the sun was absent. The most important greenhouse gas (GHG) is water vapor and the next is carbon dioxide. These two gases play a crucial role in keeping the average temperature on earth high.

While the greenhouse effect produced by these gases is critical to survival on earth, too much greenhouse effect is detrimental. The presence of excess GHG emissions has led to the increase in earth’s temperature as more heat is trapped within the atmosphere. These global warming is on the rise due to the continued emission of GHGs into the atmosphere. Scientists predict that global surface temperatures will rise a further 1.1 to 6.40C during the 21st century.

Causes of global Warming

The most significant cause of global warming is human activity. There is agreement amongst leading scientists that the increase in GHGs concentration in the atmosphere can be traced back to various human activities. Specifically, the rampant industrialization carried out by humans over the last century has contributed to global warming. To fuel the industrialization efforts, humans have relied primarily on fossil fuels.

These energy sources contribute directly to global warming since they produce CO2 as a by-product of their combustion. The global warming phenomenon has therefore been increased by the high levels of fossil fuel usage over the last century. The International Panel of Climate Change declares that if the current rate of human industrial activity progresses undeterred, there will be a doubling of CO2 levels by the year 2065 (Degelman, 2002).

There are other secondary gases produced because of human activity that have amplified the greenhouse effect on earth. Haldar (2009) notes that even though its impacts are less than those of CO2 are methane is an important GHG. Human activities related to agriculture have led to increases in methane levels in the atmosphere. Landfills and natural gas distribution have also raised methane levels leading to greenhouse effects. Nitrogen oxides produced from large combustion plants also have a greenhouse effect once they accumulate in the atmosphere.

Another human activity that has caused global warming is the aggressive deforestation. Trees act as important natural carbon sinks. These natural features remove some of the CO2 from the environment in the carbon exchange process. Haldar (2009) declares that the carbon exchange has been taking place for millenniums and it guarantees the earth’s climate stability since the amount of carbon on the planet is at an equilibrium. Through deforestation, the trees that played a crucial role in removing excess carbon have been destroyed. The destruction of forests continues to occur even as the demand for timber and land for human settlements and agricultural purposes increases. According to Guinness (2010), deforestation accounts for at least 7% of the total GHG emissions.

In addition to the human causes of global warming, some natural causes exist. A major natural cause of global warming is sunspots. The total amount of solar radiation reaching the Earth can vary due to changes in the sun’s output. This output is affected by sunspot activity. Research indicates that the solar output has been fluctuating over the past century. Haldar (2010) documents that there has been a small but gradual increase in solar output leading to radiation forcing. Reports by NASA indicate that sunspot activity has increased by nearly 0.05% per decade since the 1970 (Guinness, 2010). Since the sun is the body responsible for heating the earth, an increase in its radiation levels leads to a direct rise in Earth’s temperature.

Volcanic emissions are another natural cause of global warming. When active volcanoes erupt, various gases are emitted into the atmosphere. CO2 is one of the gases contained in volcanic emissions. Casper (2009) notes that there is a high concentration of CO2 in volcanic emissions. Due to the presence of this important greenhouse gain among the released gases, volcanic emissions contribute to global warming.

Environmental Impact

A number of damaging environmental effects are blamed on global warming. Haldar (2009) reports that global warming is responsible for the raise in number of severe weather conditions experienced in many regions all over the world.

There have been increased intense tropical cyclone activities over the past few decades. The areas affected by drought have also been rapidly expanding due to global warming (Degelman, 2002). Global warming has led to the prevalence of heat waves and forest fires in some geographical regions. The destructive Tsunamis experienced over the last decade have also been attributed to global warming.

This phenomenon has threatened the lives of people living in coastal areas and islands due to the rise in sea levels. The rise in global temperatures has caused glaciers at the south and north poles to melt. This has increased the water volumes in the oceans leading to a rise in sea levels. Islands lying at low altitudes and coastal settlements have faced threats of large-scale flooding due to the rise in sea levels caused by global warming.

Marine lives have been adversely affected by global warming. To survive in the water bodies, organisms require adequate amounts of oxygen. Global warming has led to oxygen depletion by promoting the growth of seaweeds that consume most of the oxygen. This has an adverse effect for ocean life. In addition to this, the ocean temperature changes caused by global warming have been harmful to some marine life. For example, coral reefs require specific water temperatures to survive. The changes in water temperature caused by global warming have led to the wiping away of coral reefs in some regions.

Global warming is detrimental to agricultural practices. As such, this phenomenon has a negative effect on food supply. Some of the adverse effects of global warming include drought, high evaporation, and an increase in the occurrence of extreme weather events such as heat waves, tornadoes, and floods. Casper (2009) declares that farmers will experience decreased crop yields due to these environmental changes caused by the rise in global mean temperature.

Global warming is blamed for the increase in diseases especially in the tropical regions. According to Casper (2009), global warming has altered the distribution of some infectious diseases. This has increased the exposure that most people have to these diseases leading to illnesses and even deaths.

Solutions to Global Warming

Considering the significant negative effects of global warming, solutions are urgently needed to mitigate this phenomenon. One solution would be to stop the use of fossil fuel powered vehicles. As it currently stands, vehicular emissions contribute the greatest percentage of greenhouse gas emissions globally (Guinness, 2010). Any reduction in the use of vehicles would dramatically reduce the GHG emissions therefore mitigating global warming. In place of the fossil powered cars, electric cars can be used.

A switch to renewable energy sources would also contribute to the mitigation of global warming. As noted, power production has been the main cause of the global warming experienced over the last century. Humans primarily rely on fossil fuels to provide for their energy needs. The combustion of coal, oil and gas to provide for these needs has increased the CO2 levels in the atmosphere leading to global warming (Casper, 2009).

Moving to renewable energy sources would remove the reliance on fossil fuels. By utilizing sources such as solar panels and wind turbines, the global community will be able to obtain energy without producing GHGs. Increasing reliance on renewable energy sources will therefore be a major solution to mitigating the global warming crisis currently being faced.

Expansive tree planting efforts can also play a part in the mitigation of climate change. As noted, trees act as natural CO2 regulators. The decline in tree cover has contributed to the increase in global warming over the decades (Haldar, 2009). Increasing the quantity of trees will reduce the CO2 in the atmosphere since they act as carbon sinks.


This paper set out to define global warming and highlight the causes, impacts, and solutions to this global phenomenon. It defined global warming as the rise in the average temperature and showed that human activities over the last 2 centuries have been the main causes of this phenomenon. The paper also noted that natural events such as volcanic eruptions and sunspots have contributed to global warming. A number of the adverse environmental effects of global warming were articulated. Some of the solutions that can help deal with global warming have been provided. These solutions should be implemented to prevent global warming from causing phenomenal damages to the world.


Casper, J. (2009). Changing Ecosystems: Effects of Global Warming. NY: Infobase Publishing.

Degelman, L.O. (2002). Which came first – building cooling loads or global warming? – a cause and effect examination. Building Services Engineering Research & Technology, 23(4), 259-267.

Guinness, P. (2010). Geography for the IB Diploma Patterns and Change. Cambridge University Press.

Haldar, I. (2010). Global Warming: The Causes and Consequences. Boston: Mind Melodies.