Bryan Lawrence : Bryan's Blog 2005/07/21

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Bryan's Blog 2005/07/21


Quite often I have to make tiny modifications to existing pdf files.

I've just found flpsed and it works!

I downloaded it and the Fast Light Toolkit, and a few minutes later I could do it. Installing flpsed was a wee bit annoying on my Suse (still 9.2 dammit) system:

  1. Configuring, making and installing fltk was a doddle.

  2. The Configure for flpsed couldn't find the fltk though, I had to do this:

    ./configure FLTKCONFIG=/usr/local/src/fltk-1.1.6/fltk-config 

Then it's straight forward to use. Take a pdf document. Use pdf2ps to produce a postscript file. Annotate (not edit) it with flpsed, and then export the result as pdf. Done.

by Bryan Lawrence : 2005/07/21 : Categories computing (permalink)

Icehouse and Greenhouse Worlds

I've been ignoring paleoclimatology for a long time as being yet another interesting field, that I haven't time to pay attention to. However, today's lunch time reading was Kump's letter to Nature which introduced me to the concept that in the Eocene (55-34 million years ago), the earth was thought to be essentially warm and ice free most of the time, associated with higher levels of CO2. However, apparently that all changed at the Eocene-Oligocene boundary, when the earth moved into it's current glaciated state i.e masses of permanent ice over Antarctica and elsewhere.

It turns out that during the Eocence there probably were glaciations but they didn't persist. The hypothesis advance for the transition into the Oligocence with permanent glaciation (or why earlier "minor" glaciations didn't persist) seems to be related to a rapid drawdown in atmospheric CO2 resulting from increased weatherability of the continents associated with Himalayan uplift.

There were two things I took from this:

  1. I had no idea that weatherability of rocks could be so important for the atmospheric CO2 loading (ok, I should have, I've heard colleagues witter on about this in the past, but hadn't paid enough attention), and

  2. Kump's final conclusion:

    If decreasing atmospheric CO2 stabilized the glacial state in the Oligocene, might increasing atmospheric CO2 from fossil-fuel burning destabilize it in the future? The lesson to be learned here is that we should watch for subtle signs that we are moving from the icehouse world in which Earth has remained for 34 million years into a new, greenhouse world.

by Bryan Lawrence : 2005/07/21 : Categories climate (permalink)

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