How much light the sun emits affects the Earth's weather and climate. And sunspots—dark dots on the face of the great fusion reactor in the sky—do alter the orb's output. So when solar scientists said last week that sunspot cycles might be going into hibernation, the impact on our planet's climate became a hot topic.



Previous prolonged weakenings in the solar cycle may have launched mini-Ice Ages. An example is the so-called Maunder Minimum in the 1600s and 1700s when the Thames River routinely froze, something that never happens today.



So if we're to face a temporarily cooler sun, maybe all those greenhouse gases we've been putting into the atmosphere will keep us toasty?



A cooler sun might mean a drop in global average temperatures of at most 0.3 degree Celsius. But the carbon dioxide already in the atmosphere today will add 0.6 degree Celsius to global average temperatures by the end of the century. And more, since greenhouse gas emissions show no signs of diminishing. So the slightly cooler sun won't counteract a much hotter Earth.

—David Biello

[The above text is an exact transcript of this podcast.]