On 28/11/2019 20:27, Len wrote:
On Thursday, November 28, 2019 at 1:27:58 PM UTC, Martin Brown wrote:
On 28/11/2019 11:53, Weather or Not wrote:
On 28/11/2019 11:12, Alastair B. McDonald wrote:
Â*Â*Â*Â*Â*Â* "Carbon dioxide in the atmosphere is at an all-time high,
according to the World Meteorological Organization. The last time the
Earth experienced concentrations of CO2 near today’s levels was
millions of years ago when temperatures were 2-3 degrees Celsius
warmer and than sea level was 10-20 meters higher. Scary? Yes. Yes, it
is. – via NBC News"

Why are temperatures and sea levels not higher?

The same reason that June, when the sun is highest in the sky is not the
hottest month of the year in the UK. Thermal inertia matters.

The oceans have immense thermal inertia and so the response to today's
GHG forcing lags behind. When the oceans do eventually catch up with the
equilibrium conditions appropriate to the present levels of CO2 in the
atmosphere sea levels will be higher. A some future warming is already
locked in even if we stopped the CO2 level from rising tomorrow.

However, as things stand the oceans are chasing a moving target since
CO2 levels and other GHG contributions continue to rise year on year.


What about clouds and cloudiness?
Must play a significant, unspecified as yet, role.

Clouds are very much a double edged sword.

Thick dense ones reflect sunlight up and away but also trap heat against
the ground with a slight net cooling effect. The strongest effect is to
clamp the diurnal temperature excursion to be closer to the mean.

Thin high cirrus and higher water vapour content of a warmer atmosphere
still let most of the sunlight through but make it harder for thermal
long wave IR to escape. Net warming potentially quite strong.

Lindzen's Iris hypothesis made a serious attempt to use clouds to limit
the effect of CO2 rise in the tropics but it was not borne out when it
was tested experimentally. Some debate still exists as to whether or not
it could still play a part in limiting AGW.

I view him as a true scientist despite his denialist tendencies he was
genuinely making a serious effort to refine the climate models.

https://en.wikipedia.org/wiki/Iris_hypothesis

References at the bottom to primary literature.

You have to look very carefully at the affiliations and credentials of
anyone claiming to have strong evidence for the Iris hypothesis - they
are usually in hock to Australian, US or USSR fossil fuel interests.

--
Regards,
Martin Brown