Palm trees 'grew on Antarctica' | Hacker News Reader

Palm trees 'grew on Antarctica'

bbc.co.uk

27 pointsZenst12 comments

This strongly suggests that the idea of "run away" greenhouse effect, wherein the Earth latches into a permanent irreversible hotter state ("like Venus", the media was saying back in the 80s and 90s) is not true: the Earth has been 10-20 degrees F warmer in the past and has declined from there.

Yea its been known for a long time that that was the case. The problem with modern climate change is the speed at which its changing. In the past plants and animals evolved to deal with changes as they appened over millions of years, and now they have to adapt in just a few decades which is impossible for most.

Obviously the earth hasn't latched into a "permanent irreversible hotter state". The present climate and the fact that we even exist to talk about it demonstrates that. What exactly are you trying to say?

And the fact that the earth is cooler now than at some arbitrary time(s) in the past doesn't prove that such a state isn't possible either, only that it hasn't happened yet.

The earth was 5-10 degF warmer in the Middle Miocene, about 15-20 million years ago. Inferring from this that global temperatures are following a declining trend is extremely misleading.

> Obviously the earth hasn't latched into a "permanent irreversible hotter state". The present climate and the fact that we even exist to talk about it demonstrates that. What exactly are you trying to say?

There are two ways that we might not have latched into a runaway greenhouse effect:

1) the effect exists with a trigger temperature, and we have never hit that trigger temperature

2) the effect does not exist.

The fact that Antarctica has been tropical and is not now suggests that #1 is false.

> Inferring from this that global temperatures are following a declining trend is extremely misleading.

WHERE did you get the belief that I was suggesting that?

All I said was that apparently there is not an unrecoverable latch-up in the next 10-20 degrees.

There's always a global warming denier...

The climate stayed in the warm state described in the article for some 20,000,000 years.

Which is to say a few thousand times longer than all of recorded human history.

Anything over 100 years is "permanent" as far as humans are concerned. The climate could easily change for a period of time that is 5 or more orders of magnitude larger than "permanent".

TL;DR: You're engaging in dumbass wordplay.

> There's always a global warming denier...

I did not REMOTELY deny global warming. I said that the propaganda that there's a irreversible "cliff" is false.

> Anything over 100 years is "permanent" as far as humans are concerned.

So the Medeival Warm Period, and the Little Ice Age were both "permanent"?

I think

Gets me thinking of the probably unique animals that would have evolved there.

Who knows? Maybe a large part of us came from there.

Episode 5 of Walking with Dinosaurs was dedicated to Antarctica. Their setting is another 50 million years earlier, as the title implies, but it may interest you nevertheless.

Evidence of a shift in the geographical poles some time in the past?

In terms of geology/geography, 50MYA is not long ago really - the land masses were broadly similar to those today, and the poles probably were too:

http://en.wikipedia.org/wiki/File:Paleogene-EoceneGlobal.jpg

So it's more that the climate was dramatically different over the entire globe, with more CO2, and a dramatically higher temperatures, with sub-tropical poles.

To clarify, I wasn't so much thinking of continents drifting relative to each other, rather something like the Earth's crust slipping on the molten mantle so that the continents all moved together from equator to pole and vice versa. I remember hearing some potential evidence for this (but don't have any links to hand).

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