Is climate change natural or caused by humans?

By Sarah Ruel, Jack Poratti, Tim Dorr, and Orin Ilsley-Hoile

Yes, climate change is natural AND is caused by humans. 

The natural causes such as solar emissions, Earth’s orbit, and volcanic eruptions play a small role in climate change and global warming. The effects of human activity, fossil fuels, and greenhouse gasses emitted from humans are the main cause of Climate change. There are many scientists and experiments to back up the scientific evidence of that. The people who argue that climate change is natural, argue that what we have done as a human race is not significant enough to have impacted the climate globally. They also tend to blame it on the natural changes in climate in the past but fail to see that it is the rapid rate of the current warming period that is worrisome and caused by human activity. In a sense, they go hand in hand.  

Origin and Prevalence 

Some scientists, as well as regular civilians argue that climate change is natural. They believe that the Carbon Dioxide emissions from humans is not great enough to have an impact on the climate and ecosystems. They argue that because the gases are absorbed through the ecosystem and oceans, that there is not enough to cause an impact on our climate.  

What they do not take into consideration is the human origin of global warming. While they are correct in saying that the ocean and ecosystems absorb Co2, they do not filter it at a fast-enough rate to override the effect of human activities and emissions.  

Many skeptics of the human involvement of climate change base their claims on the fact that our technology can do great things, but if we cannot predict next week’s weather accurately, then how can we predict the weather in 100 years? This “doubting question” is what anti-climate change people base their opinions on. Most of their unscientific (not based on data) ideas stem from the believability of data we have already collected and studied. They believe that scientist’s data could have been misused or misunderstood.  They still believe in global warming as well as Carbon Dioxide’s part in the warming trend, however, do not blame humans.  

The important difference between not believing in climate change and the causation of the change is huge. To not believe in climate change, it shows that nothing will be done to solve it. However, whether accurate or not, the people who believe that the warming trend is there naturally is enough, because that calls for action to be taken against climate change. 

Issues and Analysis   

All life depends on the energy output from the sun. About half of the Sun’s light passes through Earth’s atmosphere to the surface where it is then absorbed and reflected up into the atmosphere in the form of infrared heat. About 90 percent of that heat is absorbed by greenhouse gases and radiated back toward the surface, causing the Earth to warm. So, does that mean the sun is to blame and not humans? While it has some impact, since 1978 there has been a series of satellite data that shows a slight drop in the energy, showing the Sun is not responsible for the warming of the earth over the past few decades. Long- term estimates of the amount of energy put off by the sun also suggests that these changes in the suns output only account for 10 percent of the 20th centuries warming. 

Kim Cobb, a climate scientist at Georgia tech says that the natural causes of climate change such as solar cycles, Earth’s orbit, and volcanic eruptions do cause slight periods of warming and cooling. However, none of said natural causes can explain the current warming trend.  

Cobb goes on to explain that the current concentration of global warming pollution can be the only explanation. This is proved by studying what would happen if the greenhouse gases were removed from our atmosphere: When the gases are removed in a scientific simulation,  you don’t see the level of warming over the past few decades, now when you put those gases back in the level of warming is accelerated.   

Reto Knutti, a climate scientist at the Swiss Federal Institute of Technology and his co-author Markus Huber did an independent study that quantifies the human and natural contributions, with solar radiation contributing minimally. In this complicated study they concluded that natural climate variability is highly unlikely to have contributed more than a quarter of the warming trend observed over the past 60 years. About 74% of the climate variability is almost certainly because of human activity and emissions. They explained that greenhouse gases such as carbon dioxide are mainly to blame for recent global warming. In laymen’s terms, they conducted a study involving a simple model of Earth’s total energy budget (running numbers thousands of times). They used many combinations of their “parameters” which included radiation from the sun, solar energy leaving the Earth, and heat absorbed by the oceans. By using the best combination that matched the current surface warming and ocean uptake, they found that greenhouse gases contributed to 0.85 degrees C, around half of that was offset by the cooling effects of aerosols. They calculated the net value of warming to be 0.5 degrees C. (Actual temp. Rise if 0.55 degrees C). Then the warming rise was compared to the 0.07 degree C rise that was naturally contributing to climate change. They concluded that it is one part due to natural causes and 3 parts due to human activity.