Mother nature releases most of the CO2 present in the atmosphere through the decay of organic matter. In turn, most of this CO2 is absorbed by the oceans, plants and trees. Through this release and absorption process, nature has maintained a delicate balance in the CO2 concentration at roughly 300 parts-per-million (ppm) for thousands of years.
And the Earths's average temps have also remained fairly stable over the same time period.

Electric power plants (coal and gas), cars, trucks, ships, trains, and aircraft are releasing about 100 million tons of additional carbon dioxide (CO2) into the atmosphere daily, and this added CO2 accumulates year after year. To make matters worse, humans have also cut down over a trillion trees, so less CO2 is being absorbed by nature. Overall, this human activity has caused the CO2 concentration in the atmosphere to increase to about 415 ppm and rising fast.

CO2 is a 'greenhouse' gas, which means it absorbs and retains heat. Methane, and water vapor (humidity) in the air and clouds are also greenhouse gases. Without enough of these greenhouse gases in the atmosphere, the ambient air temperature would turn freezing cold at night when the sun goes down.

But, we have just the opposite problem. There's too much greenhouse gases in the atmosphere and it's increasing rapidly as our populations increase. The production of goods and services for the population (electricity, cars, food, etc) grows as the population grows, producing more CO2 and methane emissions. The worldwide climate is warming, causing changes in the jet stream and ocean currents, which in turn lead to extreme and erratic weather events, droughts, farm crop losses, and melting glaciers and polar ice.

The oceans are also warming and acidifying as they absorb more CO2 and heat from the atmosphere, and this is probably the most concerning aspect of climate warming. The heat capacity of water is very high, so ocean temps have remained stable even as it absorbed more heat. No doubt the oceans have slowed down climate warming for decades.

But now, the oceans are saturated with heat and are warming rapidly and there's no stopping it. The warming and acidifying oceans are destroying sea life and melting the polar ice caps, and self-reinforcing feedback loops have started, ie the loss of ice leads to more ocean warming, which in turn leads to more ice melting, and so on. In short, climate warming is now accelerating out-of-control.

The old saying, "life is not fair" is a harsh reality when we look at climate change. The less-developed regions of the world contribute relatively little to climate change, but will be hardest hit. The more developed and wealthy regions of North America, Europe, and Asia contribute an overwhelming amount to climate change, but will suffer the least. However, rest assured, if nothing is done to slow climate warming, all life on Earth will be seriously impacted.



https://www.ipcc.ch/srocc/chapter/summary-for-policymakers/