During the previous post, we discussed the major role that human activities, fossil fuels, and the associated carbon dioxide emissions play in the climate change being observed today. Now, you may look back at my last few posts and say, well the climate has changed for the Earth’s entire existence naturally, so the climate should continue to change at a natural rate over spans of geologic time. At this point in the posts, the debate should already be settled, that human activities are increasing the amount of greenhouse gases, and thus, increasing climate change at a rate that is unnatural, unequivocal, and alarming compared to past millennia.
You may also say, eh, we’re humans, we’ll survive, there is no way we can stop using fossil fuels for energy… It’s just carbon dioxide! Well, you would be right in the sense that modern human society is so attached to fossil fuels that it would be nearly impossible to stop its production due to public outcry, politics and a lack of alternative technologies. Wait, there are alternative technologies? We’ll save that for another time. In other words, you’d be correct, but you should also know that the world for generations to come would likely suffer extreme climatic changes as a result, unless something is done to control emissions. If no action is taken on the issue, it is likely that future generations will wonder how we didn’t see climate change coming and take action right away. Wait, people have known about the climatic threats that we are enhancing and still are not doing much about it? Good luck world…
Let’s observe some of the climatic threats that the world is currently facing.
We will begin this discussion with the graph shown above. What this is showing, is carbon dioxide concentrations dating back to 800,000 years ago, taken from proxy data such as ice cores and other direct measurements. It’s pretty obvious from the graph that the current levels of carbon dioxide are exceeding all other points by a large margin. As previously mentioned, this is characteristic of the widespread human activities which have continued to produce greater carbon dioxide emissions at a large scale, since the beginning of the Industrial Revolution. Remember that really warm period that swept through Earth some 55 million years ago? That period, the PETM, was one of the warmer periods in Earth’s climate history. Well, a recent study shows that the rate of carbon dioxide emissions today corresponds to roughly nine to ten times the amount of greenhouse gas released into the atmosphere during the PETM. Therefore, if carbon emissions continue to rise, the total amount of carbon dioxide in the atmosphere could equal the amount released during the PETM in a little more than a century. The idea that we could reach warming similar to the PETM is scary enough to imagine.
Not only are carbon dioxide concentrations rising, but so are global temperatures. More specifically, global surface temperatures have continued to rise with greenhouse gas concentrations by about 2 degrees Fahrenheit since the late 19th century. While it may not seem like much, given the huge mass of the ocean and high heat capacity of water, it takes a long time for surface temperatures to rise even a small amount. The amount of warming over the next century is almost solely dependent on how much carbon dioxide and other greenhouse gases we will emit over the next several decades. Some models project that warming could be as high as 10.2 degrees Fahrenheit, or as low as 2.4 degrees Fahrenheit, depending on the action that is taken to reduce emissions.
As a result of the increased greenhouse gases and temperatures, the climate is not expected to behave in its usual manner. Satellites and other advancements in technology have allowed scientists to assess the climate at a global level. As you would probably expect, these measurements, which have now been collected for many years, reveal the signals of a changing climate. Additionally, evidence reveals that current warming is occurring about 10 times faster than the rate of ice-age recovery warming. Finally, carbon dioxide emissions from human activities are increasing more than 250 times faster than rates from natural sources after the last ice age (climate.gov).
Now that we know the mechanisms associated with today’s warming trend, what other threats can we expect to see as a result of this warming?
Ice Sheet/Sea Ice Loss and Glacial Retreat: Both the Greenland and Antarctic Ice Sheet have lost mass, with Greenland losing more ice as the northern polar region is affected greater by the warming trends of today. Glaciers are retreating worldwide, and both the thickness and extent of Arctic Sea Ice has been significantly depleted.
Rising Sea Levels:
The rate of sea level rise in the last two decades has doubled that of the last century, which amounted to a global average of 8 inches. The rise of sea level is increasing slightly each year and is likely to pose a major threat to coastal cities over the next few centuries, when paired with the melting of worldwide ice, as well as more extreme rainfall and storm surge events associated with the next threat posed by climate change.
Greater Extreme Events:
Greater/more intense rainfall events are expected as climate change continues. While the number of record high temperature events has increased, the number of record low temperatures has decreased. While some areas can expect more drought-like conditions, other areas may receive greater rainfall and associated flooding.
The acidity of ocean waters has increased by about 30% since the beginning of the Industrial Revolution. Since the ocean absorbs carbon dioxide and transforms it into carbonic acid, the more carbon dioxide emitted into the air means the more carbonic acid it will produce. Thus, the acidity of the ocean is raised, posing a threat to marine species, corals, and fishing industries.
Other areas include decreased snow cover, extinction/migration of species, threats to crops and agriculture, desertification of land, and many more, each affecting society and ecosystems in its own way.
In order to understand the severity of the climate crisis that we are currently enduring today, it is extremely important to understand how the climate has been changed and impacted in the past. We first began with the idea of geologic time to understand that over Earth’s history, climate change occurred over these large periods of time spanning tens of thousands to millions of years in length. When we compare the changes in climate from Earth’s past, we can see that the changes occurring today are occurring at much faster, unprecedented, and more alarming rates than we have seen in past millennia. While the effects of climate change are already noticeable, it is only expected to get worse as emissions increase. We saw what happens when life alters the contents of the atmosphere in the beginning stages of life. There is only one general difference between climate change in the past and climate change today. That difference is the existence of humans and our activities associated with resource usage and emissions of greenhouse gases.
We are setting ourselves up for climatic disaster.
We are speeding Earth’s natural processes.
We are causing current climate change.
It should be our responsibility to stop it, for the sake of future generations.
Visit climate.nasa.gov for the all latest information on the current status of the climate crisis.