In the last several weeks, weather-related natural disasters have devastated many parts of the globe. From hurricanes Helene and Milton slamming the southeastern United States while wildfires surged in the northeast, to flooding across Europe, Southeast Asia, and the Sahara desert, there has never been a more pressing need to discuss the global climate crisis. Furthermore, considering the severity of misinformation around climate change and its effects in the U.S., with rumors circulating that the government is causing these disasters with some type of device, it seems imperative that we try our best to combat this misinformation with scientific facts. Therefore, I wish to provide a brief overview of Earth’s unique climate and how anthropogenic – human-caused – global warming affects that climate and leads to more frequent and severe weather anomalies. I will follow up next week on how we can continue to address climate change. The most important message I wish to convey is that there is still time to change the direction we are headed in and save the lives on this planet; but, to do that, we must understand how we got here. Please remember this as I discuss the climate crisis and the science behind it in this post.

     Earth is the only planet we have discovered with a climate capable of supporting life. This is due to our distinctive atmosphere – the protective layer of gases that surrounds a planet. Earth’s atmosphere consists of greenhouse gases – various chemical compounds (water vapor, carbon dioxide, methane, nitrous oxide, ozone) that trap heat within the atmosphere and re-radiate that heat back down to the surface of the planet. On Earth, the levels of each greenhouse gas, and their portions of the overall atmosphere, keep the planet about 33℃ (59℉) warmer than it would otherwise be, allowing the planet to maintain liquid water and remain hospitable to many forms of life. For millennia, the temperatures and weather patterns on Earth have remained within a stable climate, maintained by our atmosphere, that has allowed for the flourishing of human civilizations around the world; humans are now changing this climate.

     To examine some planets with more extreme climates, and their atmospheric makeups, we need look no further than Venus and Mars. Venus is sometimes referred to as Earth’s evil twin due to its similar size yet extremely hot climate; its surface temperature averages 464℃ (867℉). This sweltering climate is produced by its noxious atmosphere which is much thicker than Earth’s and composed primarily of carbon dioxide (CO₂). It is also thought that Venus once had liquid oceans like Earth. However, at some point, its atmosphere began trapping too much heat and the oceans began to evaporate leading to an increase in water vapor which trapped even more heat creating a runaway greenhouse effect that resulted in the complete evaporation of all the liquid water on the planet. Mars is on the other end of the spectrum. Its atmosphere is much thinner than Earth’s, less than one percent of the volume, and cannot trap nearly as much heat from the Sun. Therefore, its climate is frigid, with an average surface temperature of minus 65℃ (minus 85℉).

     So, how are we humans changing the Earth’s climate? The short answer is by increasing greenhouse gases in the atmosphere which then act as a thickening blanket warming the planet more and more. The two most dangerous greenhouse gases that human actions are increasing are carbon dioxide and methane (CH₄). Carbon dioxide is released through several human activities. The greatest amount is produced through the burning of fossil fuels – ancient sunlight, consumed by plants and animals and broken down by time and pressure to produce coal, crude oil, and natural gas (primarily methane). Fossil fuel is most commonly used during the transportation of people and goods, industrial processes, electricity production and use, plastics production and use, and heating and cooling homes and offices. However, CO₂ is also released through deforestation and agricultural practices, such as deep tilling, and the production of cement and concrete. Before the widespread use of fossil fuels and the ensuing Industrial Revolution, the levels of most greenhouse gases, especially CO₂, had remained stabilized for almost 6,000 years, encompassing the rise of modern civilizations. That is no longer the case. Carbon dioxide has been steadily rising since the Industrial Revolution and is now off the charts when compared to the rest of recorded history, from no higher than 300 parts per million (ppm) before the rise of fossil fuel use to 419 ppm today. Compounding the issue is the fact that CO₂  is capable of remaining in the atmosphere for hundreds to thousands of years, leading to a serious cumulative problem.

     Methane differs from CO₂ in several ways. In the first place, methane molecules break down considerably faster in the atmosphere, on average taking only 12 years. Therefore, it is often considered “less of an issue” than carbon dioxide. However, each CH₄ molecule can trap much more heat than a CO₂ molecule; therefore, methane has the potential to make the planet hotter but for a shorter duration. This makes it important to limit methane emissions for immediate relief from global warming but still places carbon dioxide at the forefront when considering long-term climate stability. Additionally, the largest anthropogenic sources of methane also differ from those of carbon dioxide. Though fossil fuel use does emit methane, the greatest emissions come from raising livestock and decaying waste in landfills. If we only consider cattle raised around the world for beef and dairy, the CH₄ they release when belching and farting creates a warming effect equivalent to two billion tons of CO₂.

     Now that we understand the importance of Earth’s atmosphere and how humans are changing its composition, we need to discuss the difference between climate and weather. This seems to be a differentiation that many people struggle with. Climate is the long-term average of weather patterns and can be looked at globally or regionally. Weather is the atmospheric state of a particular place and time; it can change minute-to-minute, hour-to-hour, day-to-day, and season-to-season. Therefore, a particular event, such as a thunderstorm, is an example of local weather; whereas, living in a tropical zone, like The Bahamas, would be an example of climate. Below is a video that does a great job of explaining the difference. 

     This gets us to how a warming planet can lead to more frequent and severe natural disasters, like hurricanes, floods, droughts, and wildfires. As previously discussed in “Everything Is Water”:

The hydrologic cycle is the circulation of water from oceans to the atmosphere and back to the oceans, often by way of the land. It is powered by the opposing forces of the Sun and gravity, and, therefore, never stops. The same water molecules continuously move through this system by various evaporative or condensative processes. Though the amount of water on Earth remains the same due to the atmosphere, its distribution can vary across different states (liquid, gas, solid) and locations (oceans, groundwater, glaciers, lakes, etc.). And, this last fact is where issues can arise. 

One way that a warmer planet can affect the water cycle is that warmer air both increases evaporation and holds more water. This can lead to drought from higher evaporation rates and a hotter climate; but also, to storms with more precipitation due to the abundance of water in the air. (This is true for all forms of precipitation — snow, sleet, rain, etc.)

As NASA reports, as we increase greenhouse gases and the planet warms…

Earth’s air and ocean temperatures warm. This warming affects the water cycle, shifts weather patterns, and melts land ice — all impacts that can make extreme weather worse. 

According to the Intergovernmental Panel on Climate Change (IPCC)’s Sixth Assessment Report released in 2021, the human-caused rise in greenhouse gases has increased the frequency and intensity of extreme weather events…

[And,] research says all the risks from these extreme weather events will escalate the more the planet warms.

     If we think of heat as energy (which it is), what warming the planet is doing is essentially infusing the climate system with an abundance of energy. This abundance of energy increases the risk of more frequent and severe weather anomalies. For example, though it is hard to say that climate change “caused” any particular weather event, we can say that climate change increased the chances this event would occur and increased the amount of available energy to feed this event. Below is another video that helps explain this concept.

     All of this helps explain how Hurricane Helene, a Category 4, had enough energy, and carried enough precipitation, to wreak havoc from the Florida coast, through Georgia, and inland to devastate the mountains of western North Carolina and east Tennessee with record rainfall that caused historic flooding and landslides. Overall, Helene would impact six states in the southeast and claim hundreds of lives (with hundreds still missing) to become the second deadliest hurricane in U.S. history, behind only Katrina. Then, just over a week later, Hurricane Milton would intensify from a tropical storm into a Category 5 hurricane overnight, becoming the second-strongest hurricane to ever form in the Gulf of Mexico and one of only a handful of hurricanes to have intensified into a Cat 5 within 24 hours. At the same time, wildfires rampaged through the northwestern United States destroying homes and businesses and taking lives. At some point, we must acknowledge that the cost of doing nothing about the climate crisis will far outweigh the cost of addressing it, especially when one considers the loss of lives.