What evidence is there to support that humans have increased climate change over time?

Earth's climate is changing, specifically in terms of average temperature. The role played by human beings in climate change is irrefutable. 

Earth's temperature is maintained in a more hospitable range by a number of gases present in the atmosphere. These gases (including carbon dioxide, methane, etc.) trap the heat reflected by Earth's surface and keep the planet warm. This effect is known as the greenhouse effect. It has been observed by scientists that the average temperature of Earth is increasing. They have also found that the atmospheric concentration of carbon dioxide is increasing as well. This has led them to believe that increased global warming is being caused by an increased amount of carbon dioxide.

There are a number of possible reasons for global warming, including an increased greenhouse effect, an increase in solar radiation, and volcanic eruptions, among others. The Intergovernmental Panel on Climate Change (IPCC) has clearly stated that human factors are responsible for most of climate change. Since the 1880s, the average global temperature has increased by almost 0.87 degrees Celsius. 

Climate change models have failed to match Earth's temperature by using natural factors alone. When both natural and human factors are included, the models fit the temperature trends well. The main human factor in climate change is the increase in carbon dioxide emissions, post-industrial revolution. The CO2 concentration has increased from about 280 ppm to 400 ppm in the last couple of centuries. Most of it has resulted from the consumption of fossil fuels, which fulfills our energy demands. Another factor is deforestation, which decreases the number of sinks of carbon dioxide (plants consume CO2 during photosynthesis and hence are sinks). 

Scientists have also studied the sources of carbon dioxide in our atmosphere and have found fossil fuels to be a major source of additional carbon dioxide.

Thus, human activities have caused significant climate change, especially since the industrial revolution. Scientific studies have confirmed their role in global warming.

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