The debate on climate change originally started in 1858, around the time of the Industrial Revolution. Since then, people have been suggesting that global warming is caused by human behavior on the one hand, and natural processes on the other. But who is right?
In the 20th century alone, the global temperature rose by 1.4F. In 2013, some 11,000 peer reviewed studies concluded that 97% of research found that global warming is caused by humans. A 2012 study concluded that 70% of climate change after 1850 is part of multiple solar cycles. In 2013, however, a study showed that the rate of global warming over the past century was faster than it has ever been over the last 11,300 years. Finally, in 2010, a study demonstrated that the last major glaciation (not warming) period happened between 460 and 445 million years ago. Carbon dioxide levels then where five times what they are now.
Arguing that Humans Cause Global Warming
Firstly, there is a great deal of scientific evidence that humans have caused it, with 97% to 98% of scientists agreeing with this. Furthermore, the levels of gases produced by humans that are released into the atmosphere are on the rise and this is creating a greenhouse effect. This, in turn, means that heat is being trapped and global warming is the inevitable result.
It is also obvious that the rise of CO2 levels in the atmosphere over the past 100 years is definitely caused by humans, as natural climate change could not achieve this. Historic evidence supports this. Additionally, the CO2 that is building up in the atmosphere of the earth is a specific type that is proven to be connected to human activity.
It is also not possible for natural climate changes to increase the earth's temperatures as quickly as what they are doing. The same is true for the sun's activity's natural changes, which are agreed to only have a 'minor effect'. Additionally, the Arctic ice cap is melting quicker than ever before, and this is believed to be due to greenhouse gases produced by humans. As a result, sea levels are also rising, not just due to the melting ice caps but also due to the thermal expansion of the now warmer waters of the oceans.
The levels of acidity in the oceans are also on the rise, so quickly that they must be caused by the human CO2 emissions. Because the temperature of the oceans is also rising, further climate change is occurring. Similarly, the melting glaciers are also causing extra climate change effects.
Those who say it is caused by humans also suggest that humans are responsible for the changing weather systems. This means droughts and heat waves are becoming more frequent and more intense. This is also shown by quite dramatic changes in the levels of global precipitation. At the same time, the permafrost is melting much more quickly than ever before, again leading to further climate change.
Arguing that Humans Do Not Cause Global Warming
While the pro camp is very vocal and cites some impressive sources, the con camp is exactly the same. They start by stating that some 1,000 scientists do not believe humans are responsible for climate change at all. According to them, the climate of the earth has always gone through periods of cooling and warming, and while the earth is warming at present, it is within acceptable ranges.
The con camp also saya that higher CO2 levels in the atmosphere do not cause global warming. This is because 'carbon sinks' like forests and oceans absorb the CO2 produced by humans. They also state that saturation levels are already high in the atmosphere, and any additional CO2, whether natural or man-made, will not affect this.
According to those stating that it is not caused by humans, global cooling and warming are part of the natural 'solar forcing' fluctuations. To prove this, they state that the rate of climate change has slowed down dramatically, even though levels of CO2 continue to rise. They also say that the pro camp uses computerized models that have not once been able to predict anything accurately, which means they could have this one wrong as well.
They also say that sea levels are indeed on the rise, but they have been rising for thousands of years, which has nothing to do with humans. Similarly, while there are now higher acidity levels in the oceans, these remain in normal ranges. They say that the fact that glaciers are disappearing is also nothing new, as this has been happening for thousands of years as well.
According to those who say it is not due to human activity, the cause of climate change is found in deep ocean currents instead. While they agree that there have been more and stronger hurricanes, they say that this is equally normal during these changing conditions.