At the American Astronomical Society (AAS) conference this week, three papers lead to the conclusions that Solar Cycle 24 is very weak and that Solar Cycle 25 may not really happen at all. This is bad news for our climate.
The problem with a “quiet” sun, lacking sunspots, is that when it has happened before notably during the Maunder (1645-1715) and Dalton (1790-1830) Minimums, the climate of the earth got noticeably colder. There are various theories for why this is, ranging from actual decline in solar output to decreased solar wind incident on the earth’s magnetic field, allowing more interstellar cosmic radiation to impact our atmosphere, creating more clouds and thus reflecting more of the sun’s energy back into space.
Now, I am the first to agree that correlation does not equal causation, especially with two datapoints. But if we look at the carbon-14 signal in trees (pre-1950 when nuclear testing contaminated the data), it appears that the solar activity is fairly well correlated to climate changes over the last 1200 years or so. Some have said the Maunder minimum didn’t correlate well to the Little Ice Age period, which lasted from 1300-1700. But if you consider the Spörer minimum as well, and the fact that the increase in solar activity between the Spörer and Maunder hardly reached the level of the Dalton minimum, then the solar “minimum” really lasted nearly 300 years.
If it comes to be that Solar Cycle 25 looks like the Maunder or Dalton periods, and the climate correlation holds, then next 20-50 years (or longer) could be chilly. This would be bad from the perspective of food production and my enjoyment of golf.
Recall that during the Maunder and Dalton Minimum periods, rivers like the Thames froze regularly. That hasn’t happened since 1815. And if such a cooling event does happen in the next 10 years, I can’t see how anyone will be able to sell the world on the dangers of anthropogenic climate change/global warming. So watch the news for late snow melts running into summer, early snowfalls, and record low temperatures for extended periods. London may again see a Christmas like was describe in Dickens’ novels…