It’s estimated planet earth was formed 4.5 billion years ago. It’s believed a dense atmosphere then emerged over about the first 500 million years and the oceans are thought to have formed during this timeframe or shortly thereafter in geologic time. Once we had an atmosphere, we had climate and climate change. So our climate has been changing for a long time.
Weather = conditions of atmosphere over a short period of time, where atmosphere includes temperature, precipitation, wind, etc.
Climate = conditions of atmosphere over an extended period of time, where atmosphere includes temperature, precipitation, wind, etc.
Global Warming = Rise in global average temperature. This is commonly what is meant by climate change, but technically climate is more than temperature. Rising temperatures do however result in changes to weather and climate.
Global Average Temperature Change (since 1880).
Primary contributions to climate change:
-Greenhouse gases. Man-made emission of greenhouse gases, which are primarily from burning fossil fuels (coal, oil, natural gas). Carbon dioxide (CO2) is the main greenhouse gas, but there are other gases too. CO2 is also released from natural sources like volcanoes.
-Changes in the sun’s energy reaching earth; the sun has cycles and the earth’s orbit has cycles.
-Changes in the sun’s energy being reflected or absorbed.
Climate change is complex and global warming has become the centerpiece for discussion. Everyone agrees the planet has been warming, man-made emission of greenhouses gases and especially CO2 is having an effect on warming, and future predictions are difficult, but pretty much everything else is under debate. Two general viewpoints are presented.
(1) Man’s use of fossil fuels is rapidly causing the temperature of the planet to increase and usually they say with dire consequences:
Analysis: Why Scientists Think 100% of Global Warming is Due to Humans
Scientists Agree: Global Warming is Happening and Humans are the Primary Cause
Why 4.5 Billion Years of Fluctuating Global Temperatures Can’t Explain Climate Change Today
(2) The evidence is not conclusive that man’s use of fossil fuels is rapidly causing the temperature of the planet to increase and usually they say there are not dire consequences:
Climate Change: What Do Scientists Say?
The Global Warming Crisis is Over
Climate Models and Climate Reality: A Closer Look at a Lukewarming World