JoNova

A science presenter, writer, speaker & former TV host; author of The Skeptic's Handbook (over 200,000 copies distributed & available in 15 languages).


Handbooks


Advertising


Australian Speakers Agency



GoldNerds

The nerds have the numbers on precious metals investments on the ASX



The Skeptics Handbook

Think it has been debunked? See here.

The Skeptics Handbook II

Climate Money Paper



Archives

Books

For Discussion: Can convection neutralize the effect of greenhouse gases?

Here’s an idea for commenters to sink their teeth into — Stephen Wilde postulates a mechanism where convection can neutralize the effect of changes in  greenhouse gases. The focus in David’s series of blog posts has been on radiation, but the troposphere is governed by convection.  The tropopause is the boundary where convection runs out of oomph, and above the tropopause, in the stratosphere, radiation rules supreme. Airliners like to fly at the bottom of the stratosphere (“thirty thousand feet”), just above the convection and water vapor in the troposphere, because it’s calm. But sometimes turbulence from the troposphere punches up into the stratosphere, so think of Fig 1 below if you are asked to suddenly sit in your seat and fasten your seat belt.

All the focus on radiation imbalances tends to ignore the powerful effects of gravity and convection. To get a sense of how important gravity is, ponder that a mere 3km above the surface the pressure is 300hpa lower, but gravity stops  the surface air from rushing up and equalizing that. Imagine if there were two sites on the ground where pressure was, say,  1000hpa and 700hpa, and they were only three kilometers apart, we’d [...]

Is the Sun driving ozone and changing the climate?

In 2015 the hunt for clues continues…

The central mystery in climate science is the Sun. The direct energy from the 1.4 million-kilometer-wide flaming ball stays remarkably constant. The radiation pours down on us but the relentless sameness of the watts can’t be causing of the swings in temperature on Earth. Something else is going on with the Sun. For one thing, the total light energy coming off the Sun stays almost the same but the type of light changes — the spectrum shifts –  with more shorter wavelengths at one point in the cycle and longer wavelengths at the opposite part of the cycle. These have different effects. Shorter wavelengths (UV) generate ozone in the stratosphere and penetrate the ocean. Longer wavelengths don’t. But the Sun is also sending out charged particles and driving a massive fluctuating magnetic field, both of which affect Earth’s atmosphere.

But the tiny changes in total sunlight (TSI) may still be leaving us clues about other things going on with the Sun. David Evans’ notch-delay theory is that TSI is a leading indicator, and after solar TSI peaks, the temperatures on Earth follows with a peak roughly 11 years or so later (or one [...]