Proof sought, ideas offered on warm-up

Re “Global warming -- signed, sealed and delivered,” Opinion, July 24

History professor Naomi Oreskes has produced an argument for global warming that consists in large part of an appeal to authority. She should know better; appeal to authority is one of the no-nos of reasoned debate. Oreskes needs to show us 10,000 years of corroborated data -- or better yet, 100,000 years of data -- before the scientific method will be satisfied. Then we can begin to discuss whether global warming is occurring and whether it is of human origin.

JAMES F. GLASS

Chatsworth

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I am not one of those ignorant “deniers” of global warming. We have, indeed, warmed up about 1 degree Fahrenheit since 1880 (the end of the “Little Ice Age”). No doubt about that.

Man has had a clear effect on the climate since he began farming, clearing forests and, most obvious of all, building cities. But Oreskes misses the big picture, which can be summed up in eight words: sun cool, Earth cool; sun warm, Earth warm. Just go back to the record of sunspots first begun by Galileo, who discovered them. They virtually disappeared for a century or so, and the Earth got very, very cold. They have now come back, and it’s quite a bit warmer.

Let’s not deny it: It’s the sun.

GARY DAVID JOHNSON

Topanga

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Not only are there billions of dollars of corporate oil profits at stake -- giving the energy industry virtually no incentive to seek out alternative fuels -- and given that the cost of the average new vehicle requires years of payments, meaning consumers have no desire to abandon their rides, I don’t see how the United States can end its contribution to greenhouse gas emissions in time to reverse global warming and save the planet from increasing heat.

ROBERT PIKE

Canyon Country