> >As we all know, the earth has gone through warm and cool phases in the past, and long before humans were around. Forces that contribute to climate change include the sunâs intensity, volcanic eruptions, and changes in naturally occurring greenhouse gas concentrations. But records indicate that todayâs climatic warmingâparticularly the warming since the mid-20th centuryâis occurring much faster than ever before and canât be explained by natural causes alone. According to NASA, âThese natural causes are still in play today, but their influence is too small or they occur too slowly to explain the rapid warming seen in recent decades.â
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> >Humansâmore specifically, the greenhouse gas (GHG) emissions we generateâare the leading cause of the earthâs rapidly changing climate. Greenhouse gases play an important role in keeping the planet warm enough to inhabit. But the amount of these gases in our atmosphere has skyrocketed in recent decades. According to the Intergovernmental Panel on Climate Change (IPCC), concentrations of carbon dioxide, methane, and nitrous oxides âhave increased to levels unprecedented in at least the last 800,000 years.â Indeed, the atmosphereâs share of carbon dioxideâthe planetâs chief climate change contributorâhas risen by 40 percent since preindustrial times.
