Global Warming Put in Perspective

I've just started reading "The World Without Us" which attempts to tell the tale of how the globe will recover once man is gone.

This led me to re-open the program on my iPad which charts the drift of the continents back to 540 MYA, at the start of the Cambrian Explosion of life's diversity.  (It's still Really Cool!)

It also charts the average world temperature, average oxygen content of the atmosphere and average carbon dioxide content.

Anyway, the trends put into perspective Al Gore's global warming.

Our current temp is 14.5 degrees centigrade.  The Earth has been as warm as 31 (at the end of the Cambrian, 500 MYA) and as cool as 11.9 (at the end of the Carboniferous, 305 MYA).  The Cretaceous, the last dinosaur age, (145-65 MYA) varied between 17.1 and 16.  The Triassic (250-200 MYA) was another peak, reaching 18.4.

Oxygen rose steadily until the end of the Carboniferous (33.2%) and has been declining fairly regularly ever since (21% today).

Carbon Dioxide reached a peak (0.61%) during the Cambrian -- remember, when life on Earth exploded in diversity, and the Earth was at its warmest -- and has declined, with a few peaks and valleys, ever since.  It stands at 0.04% today.  There was a long trough from the end of the Carboniferous (305 MYA) to the Permian (250 MYA) which corresponds with a dip in the average temp from 16 degrees to 12.


In other words, global warming -- if it really gets going full gangbusters -- would probably lead to another burst of evolution as nature rushes to fill all the ecological niches vacated by current cold-weather fauna like us.

Any mass extinction will be followed by an "evolutionary explosion", just because that's the way things work. But the timescales you are referencing aren't human ones. All that you, your children, your grandchildren, your great-grandchildren, etc down to really quite a lot of "greats", will experience is the dying. The subsequent explosion of life is unimaginably far in the future.

Looking back is just as bad, but people don't realize it. People think that the dinosaurs' world isn't unimaginable, but that's because they can't envision how long ago it was and don't know enough about it. They picture Costa Rica with big lizards, like Jurassic Park. But I seriously doubt that's a fair picture.

Funny. That's the exact same way I view extraterrestrial life.

Converting Celsius to Farenheit, current temp is 58.1 degrees F. Lowest temp was 53.42 and the warmest was 87.8.

So what.

That's a fairly narrow range, of what, 35 degrees? Most places get that much variation in a day. The climate would not be unfamiliar for any of the past 500 million years.

I should amend that.

During ice ages, the AVERAGE global temp may be only 53 degrees, but half the Earth is below freezing. So local temps may be quite a bit more extreme than "averages."

Perhaps you've heard of the Mini Ice Age of a few hundred years ago. That was probably mostly caused by volcanic activity, but anyway, the result was that in many areas of the Northern hemisphere (especially), winters were exceptionally severe, summers were distinctly cooler than usual, there were crop failures and much death and hardship. Not a good time.

The global average temperature dropped by less than half a degree, as far as we can tell now.

Going up in temperature will also be very disruptive, and while the IPCC wants to try and hold the rise to two degrees, most people think that ship sailed a while ago. By 2100, I expect to be well dead and gone. But I think if you have kids and grandkids, they have some trouble ahead.

I also think the time scale of my computer program may be too coarse to capture ice ages. Some of them lasted only 10,000 years or so, not the millions of the geological ages.

I've read your first post in this thread a half dozen times and still cannot figure out what the point is you are trying to make. What exactly do you mean by "in perspective."?

I guess my "perspective" was to compare projected human-caused global warming with documented variation in global temperatures per the geologic record.

IPCC wrote:

In 2001, 17 national science academies issued a joint-statement on climate change,[31] in which they stated "we support the [TAR's] conclusion that it is at least 90% certain that temperatures will continue to rise, with average global surface temperature projected to increase by between 1.4 and 5.8 °C above 1990 levels by 2100".

IPCC wrote:

Working Group III
Without new policies to mitigate climate change, projections suggest an increase in global mean temperature in 2100 of 3.7 to 4.8 °C, relative to pre-industrial levels (median values; the range is 2.5 to 7.8 °C including climate uncertainty).

These compare with a 19 degree range in our planet's history, from 2.6 degrees cooler than now to 16.5 degrees hotter.

Granted, that's not within human history, nor within human survivability, but the narrow range recommended by the IPCC is a tiny subset of what this planet has experienced in the past.

It isn't important that in eons past the global temperature was higher than it is now, and I am not aware of any scientists denying the fact. What matters is the consequences of the temperature rise on the way that humanity is structured today. Long before the heat creates a threat to the survival of our species, it will destroy the structures and institutions we have put in place, and on which we depend for the continuation of our civilization.

That's a given.

But life will continue, in fact likely it will thrive.

It just won't be human life.

Global warming has heated the oceans by the equivalent of one atomic bomb explosion per second for the past 150 years, according to analysis of new research.

That's a FUCK of a lot of stored energy.