Global warming! Climate change! Earth on fire! There are a few issues in American politics that drive citizens and elected officials fervently to their battle stations. Climate change is often cited as the gravest problem of our time. It is also used as the butt of many jokes by the opposite party. I argue that beliefs should be held in confidence only when there is evidence and reason to support those beliefs. Therefore, let us examine the evidence for climate change and if it really is a defining issue of our time. Let’s look past the party stances, view the science, and then discern where we stand. That is the essence of the scientific method.
The first query: Is global warming real?
People claim that the Earth is heating up; therefore, that temperature change will affect ecosystems, food sustainability, and the global climate overall. Before we can know if the climate is changing, we need to figure out whether the planet is actually getting warmer.
As we see from this NASA graph measuring global temperature over the past 134 years, the temperature has risen about 0.87 degrees Celsius relative to 1951-1980 average temperatures (1). “The oceans have absorbed much of this increased heat, with the top 700 meters (about 2,300 feet) of ocean showing warming of 0.302 degrees Fahrenheit since 1969” (2). Additionally, 2014 was the hottest year on record only second to…2015 (3).
Certainly there has been an increase in temperature. Now, you may hear conspiracies from politicians claiming that there has not been any global warming since the beginning of the new millennium (4). However, “the rate of warming over the first 15 years of this century has, in fact, been as fast or faster than that seen over the last half of the 20th century” (5). Therefore, we know global warming is indeed occurring.
Second query: How much warming is too much?
Scientists and politicians recently agreed at the Paris climate talks that warming need to be limited to 1.5-2 degrees Celsius compared to pre-industrial times (before 1850) (6). It is argued that beyond that much warming, there would be catastrophic effects to the global ecosystem. Currently, the average global temperate is already about 1 degree Celsius higher than in 1850 (7). Therefore, we are quickly approaching what scientists consider the tipping point for climate change.
Third query: What is causing this warming?
As the world is an immensely complex and expansive place, there are many factors that can affect climate. Additionally, the universe contains many powerful events and bodies that can affect the ecosystem here on Earth. Therefore, it is necessary to account for all of these factors in order to pinpoint what is causing all this global warming in just the past 150 years. Scientists have examined solar output of energy, volcanic eruptions of sulfur, and global wobbling.
First, they examined the sun and found that “since the 1970s, the sun has been cooling slightly. Over this same time period, the Earth has gotten warmer. Most of the warming has occurred in the lower atmosphere near the Earth’s surface.” Therefore, the sun could not possibly be the culprit of the global warming we are experiencing.
Next, they examined volcanic eruption. Those scientists found that “although volcanoes do add some carbon dioxide (a greenhouse gas) into the atmosphere, people add about 100 times more! The amount of carbon dioxide that comes from volcanoes has not increased, and it’s not enough to cause global warming. Actually, the main way volcanoes can change the Earth’s climate is by causing a temporary cooling effect. After a very large eruption, particles from the eruption can stay in the atmosphere for as long as a few years, where they block sunlight and make the planet a little bit cooler.” Therefore, if anything volcanic eruptions are warming-neutral or warming-negative.
Next, the scientists examined the slow change that occurs over time in the Earth’s tilt toward or away from the Sun. They found that “cycles in the Earth’s orbit happen so slowly that they cannot account for the rapid warming we are seeing today. Also, the current position of the Earth’s orbit should result in cooler temperatures, but instead, the opposite is happening—the average temperature of the Earth is getting warmer” (8). Again, it seems that global wobbling would have a warming-negative effect if anything.
That leaves us with one foreseeable conclusion: Something is occurring on Earth to cause this rapid warming. This would have to result from the emitting of substances into the atmosphere that block heat from escaping back into space. Scientists know that certain gasses can trap heat when emitted into the atmosphere. Gasses like carbon dioxide, methane, and nitrous oxide contain this power. Therefore, if these gasses were to exist at greater levels in the atmosphere, more heat would be trapped and the planet would warm. Carbon dioxide seems to be the leading culprit for global warming as it has the ability to remain in the atmosphere for over a hundred years compared to methane which stays around for about a decade. Therefore, the injection of CO2 into the atmosphere can have a much more enduring effect on trapping heat.
This is how such heat-trapping emissions cause the planet to warm.
When scientists examine the data, they find a drastic change in CO2 levels in the past 150 years compared to the previous 800,000 years. Such levels are trackable through their composition in frozen ice cores in the Antarctic. Every winter a new sheet of ice freezes over the Antarctic leaving frozen in time the atmospheric composition from which the water froze. The data displays stark results.
As shown, the CO2 levels are literally almost off the charts compared to the past 800,000 years. Additionally, we know that there are other emissions driving global warming, but there is far more CO2 in the atmosphere compared to other gases. Therefore, scientists determine that carbon dioxide is the main driver of global warming.
As seen in the graph above, CO2 has three times the effect on global warming as methane. This is important to note as some people claim that methane is to blame for all the warming, and methane can come from sources such as animal waste; therefore, the animals are to blame. However, as stated previously, methane stays in the atmosphere for only a tenth of the time of CO2 (9).
Furthermore, knowing that CO2 stays in the atmosphere for so long, we have not experienced all the warming that already-emitted CO2 will have on global temperature. Scientists have determined that due to this fact, we have already emitted 66% of all the carbon that will heat the globe to 2 degrees above pre-industrial levels (7).
Fourth query: How do we know that humans are responsible for all this CO2?
Maybe the CO2 is not coming from human activity, though. Perhaps there is some other kind of force injecting all of this carbon dioxide into the atmosphere.
Well it just so happens that fossil fuel carbon has a distinct composition unlike other natural forms of CO2. That fossil fuel carbon is what exactly matches the increasing levels of CO2 in the atmosphere (10). Human fingerprints are all over the CO2 influx.
Fifth query: Can’t nature absorb the extra CO2?
Early in science education, we learn that humans breathe oxygen and exhale CO2, whereas tress do the opposite. Therefore, trees can suck up the CO2 in the atmosphere. Additionally, oceans absorb CO2 as well. All of this works perfectly when the ecosystem is in perfect balance. However, introducing an outside force with additional CO2 can leave the system out of whack.
In this depiction, we see that as the seasons pass with trees growing and dying, the CO2 composition from trees is perfectly in balance. This follows exactly for the oceans as well, which absorb CO2 but also give it off in the form of water vapor. The addition of an extra 29 parts per million of CO2 into the atmosphere can throw off that precious balance.
“Consider what happens when more CO2 is released from outside of the natural carbon cycle – by burning fossil fuels. Although our output of 29 gigatons of CO2 is tiny compared to the 750 gigatons moving through the carbon cycle each year, it adds up because the land and ocean cannot absorb all of the extra CO2. About 40% of this additional CO2 is absorbed. The rest remains in the atmosphere, and as a consequence, atmospheric CO2 is at its highest level in 15 to 20 million years (Tripati 2009). (A natural change of 100ppm normally takes 5,000 to 20,000 years. The recent increase of 100ppm has taken just 120 years)” (11).
These negative effects on the atmosphere are even multiplied by the fact that humans are destroying the world’s forests. The following is a depiction of the loss of forestry in South America (12).
Therefore, human actions are even debilitating nature further from being able to mitigate the influx of CO2. We are burning the candle at both ends.
Sixth query: So what if the Earth is warming? How do we know that will affect the climate?
Occasionally, people will say that scientists no longer say global warming and instead say climate change due to the fact that it is still cold in some places. This is a clear misunderstanding of the science for many reasons that we will explain. For one, we have already seen that global warming is simply that–the global temperature increasing. An increase in global temperature then causes climate change. The two are separate events but are intrinsically connected. Let’s find out how.
First, when we imagine a warmer Earth, we think first of ice melting. As temperatures increase, it is more difficult for water to stay under freezing temperatures. Now, one may ask: so what if there is less ice at the poles? How will that cause climate change?
The explanation is quite intuitive. Ice is actually known as the most reflective substance on the Earth. Its pure white and bright color allow light to bounce off it and back into space. The more heat that ice encounters, the more likely it is to melt. When ice melts, it joins the ocean as liquid water. Ocean water is known as the least reflective substance on the Earth. Just like a black shirt outside on a summer day absorbs much more heat than a white shirt, the ocean absorbs much more of the sunlight that it encounters. Therefore, this is a dangerous feedback loop. High temperatures heat ice; ice melts to become dark ocean water; dark ocean water absorbs even more heat; temperatures increase causing even more ice to melt.
The Arctic at the North Pole is almost all sea ice meaning that it does not exist on top of land (13). Therefore, when this ice melts, it does not expose terrain but turns completely into ocean water. Additionally, as temperatures increase, this new liquid water can turn to water vapor. Some may counter that this would then counteract sea level rise. However, for one, water vapor acts as a heat-trapping gas which can have some effect on global warming. However, this effect is only marginal since water vapor “has a short cycle in the atmosphere (a few days) before it is incorporated into weather events and falls to Earth” (7). Therefore, water vapor will soon condense back into precipitation and rejoin the ocean water.
That brings us to the first effect of global warming: sea-level rise. Higher oceans intuitively mean less land for humans to use. “Over the period 1901-2010 global mean sea level rose by around 20cm and has been rising by about 3mm a year since the early 1990s…Current levels could be as little as one-fifth of the eventual sea-level rise associated with a 2°C world” (7). That would mean an additional four feet or more in sea levels across the globe. These few feet can have serious implications for cities and populations near the coasts.
Unfortunately for the United States, this means serious implications for coastal states like California, Florida, and New York. These states have high densities of people in their major cities, which would mean massive displacement as a result of sea-level rise (14).
The danger does not stop at mere sea-level rise.
“While warming oceans may not produce more tropical storms and hurricanes – they may even produce fewer – those storms will be more intense, and with longer dry spells between them. More sporadic precipitation, combined with earlier snowmelt, particularly in mountains like the Rockies, will increase the risk of wildfires.
A study published in 2007 in the journal Climate Dynamics predicted wetter winters for the northeastern United States – with 10 to 15 percent more precipitation – and hotter summers, with increasing drought over the next century as things heat up.
A 2010 report by the National Research Council, to which Pierrehumbert contributed, breaks down a series of incremental changes. Each one degree increase could mean up to 10 percent less rainfall during the Mediterranean, southwest North American and southern African dry seasons, and a corresponding increase in Alaska and other high latitudes of the Northern Hemisphere. It also could mean up to 10 percent less stream flow in some river basins, including the Arkansas and the Rio Grande, and an up to 15 percent reduction in the corn crop in the U.S., Africa and wheat in India. Each degree could also bring up to a 400 percent increase in area burned by wildfire in parts of the western U.S. And the dizzying array of impacts the authors project widens as the increases rise above two degrees” (14).
We can see that the effects of global warming are far reaching and extremely dangerous. The costs will continue to multiple as well. More intense storms will mean even more money needed to clean up the damage. More droughts will mean food shortages. More wildfires will mean more homes and forests destroyed only making global warming even worse.
Due to extra CO2 being absorbed by the oceans, the world’s oceans actually become more acidic. The change in the acidic balance of the oceans can have massive effects on the fishing industry, ocean-life food chains, and coral ecosystems (15). On the surface and in the ocean, food supply will be drastically affected by global warming.
These damages to food supplies, cities, homes, and health could have massive effects on economic growth. The cost of fighting climate change will be especially felt by some of the world’s poorest regions (16).
For the United States specifically, “A one decade increase in delay length is on average associated with a 41 percent increase in mitigation cost relative to the no-delay scenario” (16).
The following are predictions of the climate change that will occur in each region of the United States:
“Northeast. Heat waves, heavy downpours and sea level rise pose growing challenges to many aspects of life in the Northeast. Infrastructure, agriculture, fisheries and ecosystems will be increasingly compromised. Many states and cities are beginning to incorporate climate change into their planning.
Northwest. Changes in the timing of streamflow reduce water supplies for competing demands. Sea level rise, erosion, inundation, risks to infrastructure and increasing ocean acidity pose major threats. Increasing wildfire, insect outbreaks and tree diseases are causing widespread tree die-off.
Southeast. Sea level rise poses widespread and continuing threats to the region’s economy and environment. Extreme heat will affect health, energy, agriculture and more. Decreased water availability will have economic and environmental impacts.
Midwest. Extreme heat, heavy downpours and flooding will affect infrastructure, health, agriculture, forestry, transportation, air and water quality, and more. Climate change will also exacerbate a range of risks to the Great Lakes.
Southwest. Increased heat, drought and insect outbreaks, all linked to climate change, have increased wildfires. Declining water supplies, reduced agricultural yields, health impacts in cities due to heat, and flooding and erosion in coastal areas are additional concerns” (17).
The influx in heat waves and shorter winters will mean more heat-related diseases and illnesses for humans.
“In 2003, for example, extreme heat waves caused more than 20,000 deaths in Europe and more than 1,500 deaths in India. Scientists have linked the deadly heat waves to climate change and warn of more to come.
In addition to heat-related illness, climate change may increase the spread of infectious diseases, mainly because warmer temperatures allow disease-carrying insects, animals and microbes to survive in areas where they were once thwarted by cold weather.
Diseases and pests that were once limited to the tropics — such as mosquitoes that carry malaria — may find hospitable conditions in new areas that were once too cold to support them.
The World Health Organization (WHO) estimates that climate change may have caused more than 150,000 deaths in the year 2000 alone, with an increase in deaths likely in the future” (18).
The world is clearly a much more harmful and more expensive place to live if we do not stop this climate change.
Last query: How do we stop this from getting worse?
We have learned that carbon dioxide emissions are the main driver of global warming and, therefore, climate change by far. Thus, we need to end our dependence on fossil fuels. Much of what we do is still operated based on systems that consume fossil fuels. Just 10% of energy consumption in 2014 came from renewable energy sources (19). Solar and wind energy generation is increasing, but more work needs to be done. It is of utmost importance to have government and businesses committing money to research into green technologies.
If the government ends its subsidies in the fossil fuel industry, it can instead focus on renewables making them cheaper and more enticing for businesses to adopt. Bringing down the cost for businesses is imperative. Also, consumers need to be able to afford the cost of energy-efficient appliances and automobiles. As we learned previously, acting sooner rather than later will save money and further environmental damage in the long term.
If we begin to invest in renewable energy in a significant way now, businesses will naturally transition into greener practices. Fossil fuels have been far too cheap not to utilize over the past 150 years. It is the natural tendency of businesses to focus on cutting short-term costs; however the long-term costs of not acting on global warming are much more immense. That is why we need to put pressure on business and government to work together to fund research and development. We do not have to face the dilemma of choosing a survivable environment or a functioning economy. We just need to commit to creating new jobs and cheaper production in the renewables industry so that our economy can thrive while we save our only home. We need to end the carbon-based economy before the Earth becomes so hot that the negative feedback loops of global warming are unstoppable. We need to act now.
*For a comprehensive visual presentation of these same studies and conclusions, check out this video from PBS: https://www.youtube.com/watch?v=ffjIyms1BX4″