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Dear Tom,
I would like your opinion about global warming. Is it a fact or is it fiction?
John Georgar

Dear John,

Global warming is a fact, and it is occurring. The planetary average temperature of the Earth’s atmosphere at ground level is increasing. The Earth’s climate has experienced many natural fluctuations in the past — natural in the sense that they occurred without human influence. Most recently, the Earth’s climate has been growing warmer since the last glacial maximum that reached its deepest chill about 12 thousand years ago. Global temperatures have risen about 12 degrees since then and nine degrees of that warming was accomplished before humans entered the picture. However, the upward trend in global average temps has accelerated over the past 50 to 100 years, likely due to industrialization.