These greenhouse gases act like a giant blanket for the Earth, helping it to retain heat. And when the concentration of greenhouse gases goes up, it’s like adding another layer of blankets. When this happens, then global warming, or an increase in the average worldwide temperature caused by higher concentrations of greenhouse gases in the atmosphere, is the logical result.
Now, this may sound theoretical, like I’m guessing that if CO2 levels rise, then we expect the Earth to get warmer. However, the fact is we have actual scientific evidence that when CO2 levels rise, so does the average temperature of the Earth.
This is one of the closest correlations that you will ever find in the natural world. The history is clear. In the past 800,000 years, whenever CO2 levels rise significantly, the temperature rises too.
There’s one other interesting thing to point out about past CO2 levels. In the past 800,000 years, the concentration of CO2 never rose much above 300 parts per million – that is, until about a hundred years ago, when we hit right through the 300 mark on the way to our present level in 2012 of a little over 390 parts per million.
So what will happen now? There are lots of different estimates and claims that many people make, but in the past century the global temperature has risen 1.4 degrees Fahrenheit. That may not seem like a lot, but the temperature has been rising at a faster rate in the last few decades. In addition, we have 800,000 years of history that show that temperature is highly correlated to atmospheric CO2 levels. We are continuing to burn fossil fuels, and the atmospheric CO2 levels continue to rise at a steady, predictable rate.
All of the scientific data says that the Earth is getting warmer and will continue to warm up for some time. The polar ice caps are melting, and glaciers around the world are receding. The estimates for how high and how fast the sea level can rise if or when these sheets of ice melt are all over the board and depend on many factors that may come into play. If the oceans warm up, then there will be an increase in water vapor in the atmosphere. In addition, some scientists warn that there are massive stores of methane in the oceans that may be liberated into the atmosphere if the oceans warm up.
Since methane and water vapor are greenhouse gases, adding more of them to the atmosphere could further accelerate global warming.
Earth’s Changing Climate
Hurricane Katrina, Superstorm Sandy, Extreme droughts in Northern Nigeria Dangerous flooding that occurred in Nigeria displacing more than 250,000 families, dangerous blizzards on both the east and west coasts. Mile-wide tornadoes in Oklahoma, and the recent wildfires in Colorado and the Southwest United States. All of these examples are the direct result of an unprecedented increase in greenhouse gas concentration in the atmosphere – a problem that is rooted in human activity.
As explained in our previous blog, Greenhouse gases are gases in the atmosphere that allow sunlight to pass through and reach the earth’s surface. Some of this sunlight is captured as heat on Earth, and some of it is radiated back towards space. Without greenhouse gases the temperature on Earth would be well below freezing. This trapping of heat under the atmosphere is called the greenhouse effect, and it is both natural and beneficial to life on Earth. So, if greenhouse gases are so good for us, why do they get such a bad reputation? The problem with greenhouse gases is that they need to be present in specific amounts.
When too little gas is present, not enough heat is trapped under the atmosphere to keep the earth warm. When too much gas is present, too much heat gets trapped, which warms the earth more than usual. The types and amounts of greenhouse gases in the atmosphere are only beneficial when they are present in just the right balance.
The Enhanced Greenhouse Effect
You now know that the greenhouse effect is both natural and necessary for our survival because it keeps Earth warm and hospitable. However, the rapid increase in greenhouse gas concentrations in the atmosphere has led to the enhanced greenhouse effect, which is when too much heat is trapped on Earth, resulting in an overall increase in global temperatures.
While we do not know exactly how much damage such high concentrations of greenhouse gas can do, we have already seen some of the effects. Rising temperatures on Earth have produced severe changes in weather patterns, such as hotter summers, colder winters and stronger storms, like hurricanes and tornadoes.
Increasing global temperature will also lead to a rise in sea levels as the glaciers and polar ice caps melt. As sea levels rise, many organisms, such as polar bears, birds, fish and plants, will lose valuable habitat, and people will be forced to move farther inland. Industries, such as agriculture and forestry, will also be negatively affected by temperature changes, which could have worldwide consequences, such as food shortages and extreme land erosion.
EPA’s Climate Change Indicators (2014)
The concept and science of Climate change by Glory Oguegbu