[INST] I don't know if global warming is really a thing? [/INST]It is widely accepted by climatologists that Earth is warming, and that humans are responsible.  On its own, warming would lead to more frequent and more intense natural disasters and shorter growing seasons in some parts of the world, though this isn't a direct effect of human greenhouse gas emissions.  But there is a significant threat of global catastrophe in the future if we continue to raise global temperatures.  For example, it's expected that rising sea levels would severely affect the US, with up to $70 billion in damage from the projected ten inches of rise in the next 90 years, with another $40 billion in indirect economic damage.</s>[INST] How exactly did humans cause global warming? [/INST]
Human activities, primarily the burning of fossil fuels like coal, oil, and gas, have amplified the quantity of greenhouse gases in the atmosphere. A buildup of these gases, namely carbon dioxide, leads to a rise in the Earth's average temperature—a process called global warming. These greenhouse gases act like a blanket, trapping heat instead of letting it escape, which in normal conditions it should. These findings are based on research and reports from the Intergovernmental Panel on Climate Change (IPCC).
Humans have increased the amount of carbon dioxide in the atmosphere, which traps heat.  The earth would actually be getting warmer even if we hadn't put more carbon into the air, but the rate of warming would be less than it is now.  Because we are pumping carbon dioxide into the atmosphere, the earth warms up faster than it would otherwise, but the amount we are adding has not yet been enough to exceed the maximum amount of warming that would happen without human influence.