Climate Change

What is Climate

The majority of people who usually partake in discussion about climate change, generally don’t even understand the basics of climatology, or what even the climate is; and how it is different from weather. Climate is the average temperature in a given area over a long period of time, whereas weather is the day to day changes we see in temperature, clouds, precipitation, humidity and wind (1). So, just to get a better of what it is I’m talking about.

This is a weather chart:

Image result for weather forecast
Figure 1.

And this is a climate graph:

GlobalTemp.png
Figure 2.

As you can see, the weather chart is depicting fluctuations in temperature from day to day which you can probably tell appear to be random, and quite unpredictable. However, from our climate graph; it is not unknown what is happening and we can clearly see a trend in the average temperature of the Earth; it appears to be going up. This is going to bring me into my next point.

Historical Climate Change

It is not secret that a change in climate isn’t anything new to this planet. Paleoclimatologists (scientists who study the history of Earth’s climate) are able to use many methods to deduce what our temperature was like thousands, even millions of years ago. These methods include, but are not limited to: drilling for ice cores, digging out sediment cores, and observing tree rings (2). By using these methods, scientists can put an accurate depiction of Earth’s climatological history into a graph:

Figure 3.

From this graph, we can see that Earth’s climate has been anything but stable since before humans have been around; so that must beg the question: “If climate change is our fault, how come it’s happened millions of years before we’ve even existed? Isn’t it just a natural process?” These are both very valid questions, and actually the center of modern climate science; that being trying to figure out why, as we saw in Figure 2., the Earth’s temperature is going up. To understand the cause for this, we must look into the past, and see why Earth’s climate has historically changed. When it comes to this, the evidence is very clear that Earth’s climate is dependent on many factors which can basically be summed up into two: sun energy, and carbon dioxide levels. While it is true that the sun’s output does impact our climate, recent data has shown an average decline in solar output; and so if the sun was the main indicator of our global temperatures, that should mean our temperature is going down too. But this isn’t what we see happening:

Image result for solar output and temperature graph
Figure 4. (3)

As we can see from this graph, solar irradiance, which is the power per unit area received from the Sun in the form of electromagnetic radiation in the wavelength range of the measuring instrument, has been going down on average ever since the 1960s. However global temperatures continued to increase, despite this decrease in the amount of energy we are recieving from the sun. So based on this, we can tell that there must be a greater force than the sun that steers global temperatures, and if we look back to the history of Earth’s climate, we are able to find out culprit:

These two graphs show how the amount of carbon dioxide and the Earth's temperature have changed over the last 650,000 years. Both graphs show a similar up-and-down pattern.
Figure 5. Data source: EPA’s Climate Indicators (2016)

These graphs are based on the Vostok ice core from Antarctica (4). They do not include the most recent increases in carbon dioxide and temperature caused by humans. As you can see, historically, it has been Carbon Dioxide levels that most prominently give us an accurate depicton of Earth’s climate; and these figures are from before humans even began to contribute their CO2 to the world. So yes maybe it is carbon dioxide that is the main decider of Earth’s climate, but how can we be so sure that it is humans that awre pouring so much CO2 into the atmosphere? Aren’t there many more natural cycles that increase CO2 levels more than humans could ever dream of? These are all fantastic questions, that lead perfectly into my next section.

Human Contribution

The facts are undeniable. From Figure 2. we clearly saw that Earth’s temperature is rising, Figure 4. shows us that solar output has indeed been going down despite our temperature continuing to increase, and Figure 5. makes the undeniable, historical connection between Earth’s temperature, and CO2 levels; so that begs the questions: Are humans to blame for a rise in global temperatures? Are we contributing more CO2 to the atmosphere than would naturally be there otherwise? Well to answer these questions, we must consult the evidence. Based on these graphs:

Graph showing increase in 3 GHGs (CO2, CH4, & N2O). From 0 to ~1800, concentrations of each were in the following ranges: CO2: 280ppm, CH4: 720ppb, N2O: 270ppb. A sharp increase begins in 1900. By 2000, CO2 approaches 400ppm, CH4 2000ppb, and N2O 320ppb.
Figure 6. (5)
global_fossil_carbon_emissions_google_chart (1)
Figure 7. (6)

we can tell that since the late 1700s, there has been an exponential increase in the amount of CO2 in our atmosphere based on Figure 6. which is pretty interesting considering our industrial revolution began in the 1760s (7). In fact, when compared to a graph representing our total emissions of CO2 into the atmosphere (Figure 7.); we see a pretty easily recognizable correlation. The fact is, is that the amount of CO2 in our atmosphere goes up significantly with increased human output, which in turn is increasing the average temperature of Earth; therefore allowing us to conclude that yes, human are responsible for the change in climate we are currently seeing take place at a rapid pace.

Effects

So now that we know that the Earth is in fact warming, and it is us as humans who are causing the warming; what’s the big deal? Is a little rise in the average temperature of the Earth really such a bad thing? I like warm weather! Well unfortunately, warming in the Earth’s average temperature is not such a good thing. Let’s begin with an effect that many people have indeed heard before and that is that the polar ice is melting. Now, a claim often given by skeptics of climate science is that NASA concluded in a paper titled “Mass gains of the Antarctic ice sheet exceed losses” (8) exactly what the title suggests; that Antarctica has been gaining land ice on average. What the study is really showing is how the net gain of antarctic land ice was slowing from 121 to 82 billion tons per year from 1992-2001. However, as any third grader will tell you, there are two major ice sheets on Earth; one of those being Antarctica, and the other being Greenland. When it comes to Greenland, a paper published in the Geophysical Research Letters (9) shows that while Antarctica was gaining ice 82 billion tons per year, Greenland was losing ice by 269 billion tons per year; making the total net loss of Earth’s ice 187 billion tons per year, and the figure is even higher when you account for the melting of glaciers and sea ice (10). So what effect does this have? Well, it is mostly responsible for a significant rise in sea level temperatures on Earth:

SeaLevel (3).png

Figure 8. Data source: Satellite sea level observations, NASA Goddard Space Flight Center (11)

Rising sea level is a threat to people who live near the ocean. Some low-lying areas will have more frequent flooding, and very low-lying land could be submerged completely. Rising sea level can also harm important coastal ecosystems like mangrove forests and coral reefs. Another disastrous effect climate change has on us, is the fact that due to the fact that CO2 levels have been rising in our atmosphere, the acidic levels of the oceans have also been rising (12):

This graph shows three lines. Each line represents the amount of carbon dioxide in the ocean at a particular place where measurements have been collected.
Figure 9. Source: EPA’s Climate Change Indicators (2016) (12)

Why is ocean acidity so important? It is due to the fact that coral reefs live in shallow tropical waters, and are made by millions of tiny animals called corals. Each coral makes a skeleton for itself, and over time, these skeletons build up to create coral reefs, which provide a habitat for lots of fish and other ocean creatures to eat, and live. Increases in the ocean’s temperature has already caused coral bleaching (a type of damage to corals) in many parts of the world. By 2050 live corals could become rare in tropical reefs due to the combined effects of warmer water and increased ocean acidity which is being caused by our consistent dumping of CO2 into the atmosphere. The loss of coral reefs will reduce habitats for many other sea creatures, and it will disrupt the food web that connects all the living things in the ocean; and I shouldn’t need to explain why breaking the bottom of a food web can be so disastrous to those who sit at the top (13). The last effect I will state for this essay, as I could probably write a whole essay dedicated to the effects of climate change, is that of droughts. As the Earth continues to get warmer, the likelihood of drought droughts occurring becomes much higher (14). According to this chart:

Figure 10. Source: Drought under global warming, Aiguo Dai

The average potential every country on Earth has for getting a drought is said to go up significantly, which will have awful effects. More droughts would mean that there’s less water available for drinking, less watering crops, and less making electricity at hydroelectric dams. This drastic decline in resources could potentially lead to huge international conflicts as extreme as wars over water. This is not a world we should want to live in.

Conclusion

Based on the overwhelming evidence that we can draw directly from the scientific literature and research, it should be very easy for one to conclude that climate change is happening, it is being caused by humans, and it will have terrible effects on us as a species. If there are any points I failed to mention, you feel I gave misinformation, or just any questions you have in general; do not hesitate to comment or DM me on Instagram.

References:

  1. https://www.nasa.gov/audience/forstudents/5-8/features/nasa-knows/what-is-climate-change-58.html
  2. http://serc.carleton.edu/microbelife/topics/proxies/paleoclimate.html
  3. http://www.uwosh.edu/faculty_staff/hiatt/Teaching/102/climate.html
  4. https://www.epa.gov/climate-indicators/downloads-indicators-technical-documentation
  5. https://www.epa.gov/climate-change-science/causes-climate-change
  6. http://cdiac.ornl.gov/trends/emis/glo_2013.html
  7. https://www.britannica.com/event/Industrial-Revolution
  8. http://docserver.ingentaconnect.com/deliver/connect/igsoc/00221430/v61n230/s1.pdf?expires=1484265256&id=89661908&titleid=6497&accname=Guest+User&checksum=6155FF54598C869B62815711F29735BC
  9. http://onlinelibrary.wiley.com/doi/10.1002/2016GL069666/full
  10. http://environment.nationalgeographic.com/environment/global-warming/big-thaw/
  11. http://climate.nasa.gov/vital-signs/sea-level/
  12. https://www.epa.gov/sites/production/files/2016-08/documents/print_acidity-2016.pdf
  13. https://www3.epa.gov/climatechange/kids/impacts/effects/ecosystems.html
  14. https://www.c2es.org/science-impacts/extreme-weather/drought