Global warming has been a growing issue since the 18th century. It refers to the increase in global temperature that has taken place since 1910, approximately. This increase in temperature is mainly due to a process called the greenhouse effect, in which certain gases, called greenhouse gases (GHG), trap heat in order to maintain Earth at a temperature that allows life to develop. Global warming has been dangerously hastened for a number of reasons; there are both natural and human influenced causes. The principal cause for global warming is the large increase in GHG emissions, specially carbon dioxide emissions. The sectors that result in the largest carbon dioxide emissions are the electricity generation sector and the transportation sector.
The consequences of global warming go beyond climate change: besides extreme weather phenomena like floods, droughts, and rising sea levels, Earth is entering a mass extinction of species. The world is losing species 100 to 1000 times faster than it’s supposed to. On top of this, global warming will lead to serious economic issues regarding food production, real estate and adaptation measurements. Climate change will result in social issues as well, facilitating conflict in vulnerable regions, and posing a real problem for the existing healthcare systems, too.
Despite how bad the situation is, Earth’s future isn’t decided yet, and there are several measures that can be taken to help, like recycling and saving electricity. However, it is essential that governments implement measures to control GHG emissions and to reduce animal agriculture. Global warming is a real problem that is getting worse everyday. It is everyone’s responsibility to take care of our planet, but starting with ourselves and raising awareness to others is already a great way to start.
Global warming has been a “hot topic” for decades, but it has been gaining even more attention these past years. Scientists, politicians and academics are constantly publishing articles, giving speeches and searching for new breakthroughs regarding the subject. Even though the vast majority of the scientific community agrees on what is going on with global warming, there are still some people who refuse to accept the existence of it. This topic’s importance is unique for one simple reason: Earth’s fate, everyone’s home’s fate, is in its hands. On the other hand, the reason why our home’s fate is determined by it isn’t simple; it’s quite complex, actually. Global warming is a very broad subject; it is thus best to start by defining what it is.
Earth receives energy through the Sun’s radiation. Certain gases, called Greenhouse Gases, or GHG, are responsible for trapping heat in order to maintain Earth at a temperature that allows life to be sustained. This process is called the “Greenhouse Effect” and without it, Earth’s temperature would be approximately 33°C lower. However, the problem is this: over the past centuries, since the Industrial Revolution, humans have been responsible for an increase in GHG in the atmosphere. This is the result of constantly increasing fossil fuel burning and deforestation. In the last century, the primary cause of global warming has been the rise in GHG. The proof is irrefutable: over the last century, Earth’s average temperature has increased by 1.5°F, and sadly, this number is expected to keep rising.
The following figure (Figure 1) shows Earth’s surface temperature has been constantly increasing ever since 1910, approximately. Nevertheless, over the course of Earth’s history, there have been several periods of time where the planet’s surface’s temperature increases; thus, based on the collected data over the last few years, we may be in a “warming period”. This is a major problem because changes in the overall average temperature of our planet, no matter how small, “can translate to large and potentially dangerous shifts in climate and weather” (EPA). The numbers speak for themselves, but, sadly, the consequences are already happening: several locations have gone through major changes regarding rainfall, and this has resulted in more droughts, floods and rain, as well as more heat waves with increased intensity and frequency.
Figure 1. Global Surface Temperature Trend (1880-2014) (NASA GISS)
Earth’s temperature is affected by several factors, and there are both human influenced causes and natural causes. Firstly, as was said before, our planet’s climate has been in constant change for centuries. Global warming naturally occurs because of the Sun’s rotation, which firstly, makes the Sun move slightly closer to Earth, and secondly, changes the intensity with which sunlight hits Earth. This parameter is often called “the output of energy from the Sun”. Just as there are natural “warming effects” on Earth’s climate, like the one just seen, there are “cooling effects”, as well. One example of a natural cooling effect is volcanic eruptions.
Even though there are several natural causes to Global Warming, there is no doubt that mankind has played the primary role in accelerating the pace at which the planet’s temperature is increasing. Since the Industrial Revolution, back in the 18th century, the “largest contributor to the increase in global warming is carbon dioxide (CO2), followed by methane (CH4). CO2 concentrations have increased from 278 parts per million (ppm) in 1960 to 401 ppm in 2015 – a 44% increase” (Canadian Institute of Actuaries).
Figure 2. Annual Mean Growth Rate of CO2 at Mauna Loa Volcano
The previous table (Figure 2) shows the overall average annual increase (corresponds to blue bars) as well as the average for each decade (corresponds to black horizontal bars) of CO2 concentrations at Mauna Loa, in Hawaii. As of March 2017, CO2’s concentration in the Earth’s atmosphere is of 407.05 ppm, and this number is only expected to keep on rising.
Just like volcanic eruptions lead to a decrease in global temperature, there are certain “man-made” factors that have a cooling effect, like aerosols: different types “scatter or absorb sunlight to varying degrees, depending on their physical properties” (NASA). Most aerosols reflect sunlight, but some absorb it, too. Models mathematicians have calculated show aerosols have had a cooling effect that has counteracted approximately half of the warming caused by GHG since the end of the 19th century. Nevertheless, aerosols aren’t evenly distributed around the world, so the impact they have is limited to a regional scale. Aerosols have a shorter residence time (10 days approximately) than GHG (100 years approximately), and so the cooling effect is very short-term, whereas the warming effect caused by the GHG is long-term. The short-term cooling effect from aerosols leads to the possibility of a hastened warming in the future, even without the increase of GHG concentrations.
The greenhouse effect caused by gases like CO2 or CH4 takes place when solar energy directed towards the Earth’s surface is reflected to the atmosphere as infrared thermal radiation. This radiation has a lower frequency than direct sunlight, and so GHG molecules absorb this radiation. This causes the GHG molecules to vibrate; this leads to the emission of infrared photons, and a lot of these photons make it back to Earth’s surface. Other gases that are not GHG but still present in air, like nitrogen and oxygen, don’t absorb this radiation. This greenhouse effect is measured as Radiative Forcing (RF), and its units are watts per square meter (W/m2). Since the 18th century, when the Industrial Revolution began, RF has increased by approximately 2.3 W/m2, and this is mostly caused by the rise in GHG and aerosol concentrations in our planet’s atmosphere.
The following figure (Figure 3) shows emissions of carbon dioxide, methane, nitrous oxide and different types of fluorinated gases in America from 1990 to 2014 expressed in million metric tons of carbon dioxide equivalents for consistency. It is pretty clear carbon dioxide’s emissions are the largest of all, by a factor of 5, at least. In the United States, emissions of carbon dioxide increased by 9% from 1990 to 2014.
Figure 3. GHG Emissions in America from 1990 to 2014
Figure 4. GHG Emissions in America Based on Economic Sectors from 1990 to 2014Figure 4 shows GHG emissions and sinks from 1990 to 2014 classified by economic sector, expressed in million metric tons of carbon dioxide equivalents as well. Emission sinks can be thought of as the opposite of emission sources: sinks absorb carbon dioxide from the atmosphere. Although there are several sectors of America’s economy that account for GHG emissions increasing, electricity generation (power plants) is the sector that has had the largest impact. Electricity generation is responsible for 31% of GHG emissions since 1990, followed by transportation, which accounts for 26% of emissions since 1990. The emission sinks correspond to the negative values in Figure 4. In 2014, 11% of GHG emissions in America were prevented thanks to net sinks that result from land use and forestation activities. The growth of forests represents a major sink because they remove carbon from Earth’s atmosphere. Sadly, practices such as biomass burning, or transforming land into cropland lead to GHG emissions, which counteract with the sinks’ effect.
The amount of available data concerning GHG emissions is astounding. Nevertheless, it’s not enough to be able to accurately determine what’s going to happen in the future, mainly because there are several factors that have an influence in GHG emissions. The Intergovernmental Panel on Climate Change (IPCC) released a report on 2013 illustrating several plausible emission scenarios. Basically, the “best” scenario involves keeping global warming under 2°C, but this is very unlikely unless GHG emissions are reduced substantially. However, the IPCC shows no inclination towards a specific pathway because the scenario that will take place does not depend on science or on anything that can be predicted or calculated. The pathway that will eventually be taken completely depends on us, on our society. How much reduction in GHG emissions are societies willing to reach in the next century?
Although we don’t know for sure what will end up happening, we do know the consequences if we don’t change: the impacts of climate change aren’t only environmental but economic and social, too. The severity of these consequences increases as global temperature rises. As it was said before, the consequences are already starting: Canada’s average temperature has increased by 1.5°C since 1950. This climate change will lead to extreme weather shifts, like heat waves, storms, floods, droughts, rainfall, and wildfires in Canada.
From a global perspective, the environmental consequences of climate change include, first of all, floods and droughts. The frequency of floods is expected to increase for more than half of the Earth’s surface, although it might decrease in some regions. On the other hand, droughts (less rainfall and drier soil) are expected to become longer in some regions and in certain seasons. These droughts could lead to water supply system issues in drier areas. Clean water supply is expected to decrease in certain areas, and the water’s quality, too. This could mean an increased competition for water in different sectors like agriculture, industry, and energy production, among others.
Another very serious consequence of climate change is a rise in the planet’s sea levels. The US Eastern coast currently has tides that are approximately up to 3 feet higher than what they were 50 years ago. Rising sea levels will lead to floods, erosion and the disappearance of low-altitude regions, putting buildings, animals, crops and populations at serious risk. Short-term consequences of this include the risk of destruction of islands like the Maldives and regions like the Netherlands. To make matters worse, “15 of the 20 biggest urban regions are located near the coast (14 in Asia) and around 200 million people reside fewer than 30 miles from the ocean” (Brath). The models that have been developed calculate that more than $1.4 trillion worth of real estate is most likely going to be at serious risk, in the U.S. only.
The scariest part of it all comes when the consequences for Earth’s ecosystems are taken into account. Over Earth’s history, climate changes have occurred, but their slow pace allows ecosystems to adapt. However, since the 20th century, “the world is losing species at a rate that is 100 to 1000 times faster than the natural extinction rate” (University of Copenhagen). Mass extinctions of species have occurred in Earth’s history five times already. The last time was 65 million years ago, when dinosaurs disappeared. Professor Carsten Rahbek, from University of Copenhagen, explains “the biodiversity crisis — i.e. the rapid loss of species and the rapid degradation of ecosystems — is probably a greater threat than global climate change to the stability and prosperous future of humankind on Earth. There is a need for scientists, politicians and government authorities to closely collaborate if we are to solve this crisis”.
Climate change has a very large impact on food production, and the consequences already started in certain areas. This has led to a sudden and large increase in price for certain foods and cereals. Rising sea levels alone represent a huge threat to food-producing areas at low altitudes. This food insecurity could lead to conflict in vulnerable regions like Northern Africa: food insecurity could have precipitated the Arab uprisings in 2011. Additionally, extreme weather phenomena such as floods, droughts and rising sea levels pose a big problem for homeland security.
These extreme weather phenomena also put human health in danger: they increase the risk of death and disability. On top of that, higher temperatures could lead to more waterborne illnesses. Poor regions with weak healthcare systems will be the most affected by this, specially the children in these regions.
The economic impacts come both from climate change and from the adaptation measures that will have to be taken. Extreme weather phenomena will deeply affect the insurance industry and the existing healthcare systems. Sectors that depend on weather, such as agriculture, tourism, forestry, transportation, mining, among others, will also be deeply affected.
Although there are solutions to stop climate change, the real challenge is putting those solutions to practice: it is time for the different governments to step up and implement the necessary measures. First of all, the emission of GHG must be considerably reduced. In order to do this, gasoline and electricity usage, among other activities, must be reduced. There already are some ecofriendly car options, but public transportation and carpooling are a good place to start.
Recycling and saving electricity are two great ways to reduce climate change. Additionally, buying energy saving products prevents a large emission of carbon dioxide. In order to decrease the emission of methane, animal agriculture must be reduced. An estimate from the Food and Agriculture Organization (FAO) of the UN shows that approximately 18% of GHG emissions are caused by animal agriculture. The best solution regarding carbon, I think, is to put a price on it: this will work as an incentive for the research in renewable energy generation and storage sources. The implementation of a tax on carbon emissions based on carbon content would promote the usage of low-carbon fuels, and the revenue could be used as an investment in research into renewable energy sources or in transit infrastructure.
The proof global warming is occurring is irrefutable. We know what the consequences are, and we know what we can do to help, as well. It is now up to us to decide what to do: this planet is everyone’s home. It is everyone’s responsibility to take care of it. Even though it may not seem like much, if we start with ourselves and try to raise awareness on what’s going on, we’ll already be helping. There are still people who care; there’s a lot of work ahead of us, but hope isn’t lost.