Re: Ways to convince people to continue to study physics

Jim Pennino wrote:

In sci.physics Dave <dwickford@yahoo.com> wrote:

Going forward in technology and society, and mindful of the climate
emergency,

 
The Earth's climate has been in a continuous state of flux for about 4.5
billion years and has gone through numerous icehouse and greenhouse
states.
 
A greenhouse state is when no continental glaciers exist anywhere and an
icehouse state is when continental glaciers do exist.
 
For 85% of its history, The Earth has been in a greenhouse state.
 
Understanding Earth's Deep Past. 2011-08-02. doi:10.17226/13111.
ISBN 978-0-309-20915-1
 
Earth is currently in an icehouse state with continental glaciers present
on both poles.
 
Sounds to me like business as usual for the Earth's climate.
 
 

Consider:
 
 
https://www.forbes.com/sites/larrybell/2011/05/03/breaking-news-the-climate-actually-changes/
 
"Fossil records reveal that atmospheric CO2 levels around 600 million
years ago were about 7,000 parts per million, compared with 379 ppm in
2005. Then approximately 480 million years ago those levels gradually
dropped to 4,000 ppm over about 100 million years, while average
temperatures remained at a steady 72 degrees. They then jumped rapidly
to 4,500 ppm and guess what! Temperatures dove to an estimated average
similar to today, even though the CO2 level was around twelve times
higher than now. Yes, as CO2 went up, temperatures plummeted.
 
About 438 million years ago, atmospheric CO2 dropped from 4,500 ppm to
3,000 ppm, yet according to fossil records, world temperatures shot
rapidly back up to an average 72 degrees. So regardless of whether CO2
levels were 7,000 ppm or 3,000 ppm, temperatures rose and fell
independently.
 
Over those past 600 million years there have been only three periods,
including now, when Earth's average temperature has been as low as 54
degrees. One occurred about 315 million years ago, during a
45-million-year-long cool spell called the Late Carboniferous period,
which established the beginning of most of our planet's (gasp)
coalfields. Both CO2 and temperatures shot back up at the end of it just
when the main Mesozoic dinosaur era was commencing. CO2 levels rose to
between 1,200 ppm and 1,800 ppm, and temperatures again returned to the
average 72 degrees that Earth seemed to prefer.
 
Around 180 million years ago, CO2 rocketed up from about 1,200 ppm to
2,500 ppm. And would you believe it? This coincided again with another
big temperature dive from 72 degrees to about 61 degrees. Then at the
border between the Jurassic period when T. Rex ruled and the Cretaceous
period that followed, CO2 levels dropped again, while temperatures
soared back to 72 degrees and remained at that level (about 20 degrees
higher than now) until long after prodigious populations of dinosaurs
became extinct. And flatulent as those creatures may possibly have been,
at least there is no evidence that they burned coal or drove SUVs.
 
Based upon a variety of proxy indicators, such as ice core and
oceansediment samples, our planet has endured large climate swings on a
number of occasions over the past 1.5 million years due to a number of
natural causes. Included are seasonal warming and cooling effects of
plant growth cycles, greenhouse gases and aerosols emitted from volcanic
eruptions, Earth orbit and solar changes, and other contributors with
combined influences. Yet atmospheric CO2 levels have remained relatively
low over the past 650,000 years, even during the six previous
interglacial periods when global temperatures were as much as 9 degrees
warmer than temperatures we currently enjoy.
 
Over the past 400,000 years, much of the Northern Hemisphere has been
covered by ice up to miles thick at regular intervals lasting about
100,000 years each. Much shorter interglacial cycles like our current
one lasting 12,000 to 18,000 years have offered reprieves from bitter
cold. Yes, from this perspective current temperatures are abnormally
warm. By about 12,000 to 15,000 years ago Earth had warmed enough to
halt the advance of glaciers and cause sea levels to rise, and the
average temperature has gradually increased on a fairly constant basis
ever since, with brief intermissions."