If the IPCC is right, we have about 12 years (144 months) to make a dramatic change in direction on
fueling catastrophic climate change. (Personally, I think the IPCC is far too optimistic, and we don't have
that kind of time to make dramatic changes if want to maintain a survivable climate. Remember, we only get
to run this unprecedented expeirment once, and our lives literally hang in the balance, so it would be
reassuring if it looked like the plan might work.)
How can I demonstrate the difference between linear change
(which will also lead us to an unpleasant end over a longer period of time) and acelerating change?
Suppose you want to borrow some money from me, as we're borrowing the future of the environment from
future residents of planet Earth. Suppose you want $1000, and I agree to lend that to you for 12 years,
where you make the entire interest payment of 5% annually in one lump sum at the end (with interest
compounding annually). In 12 years, you will owe me $1,796. That's actually a linear scenario, which might
look vaguely exponential due to the compounding interest effect.
Now let's consider a deal with an accelerating (exponential) effect. Because I'm a very nice guy,
I'm going to loan you that same $1000, but starting at only 0.25% interest (just 1/20th of the rate
in the example above), but the interest rate doubles each year. Again, you pay nothing until the
end of 12 years. Heck of a deal for you, right? Just 0.25% interest, and no annual compounding!
Seriously, this is pretty sweet! At 5 years you have only accrued $77.50 in interest. No problem, right?
It may come as a shock to you that your total owed at the end of 12 years is actually $11,237.50 -
over 11 times the original $1000 loan amount. That's the reality of accelerating change
(exponential growth).
We may have to talk about the collateral for securing that loan. How about the survival of your children
and grandchildren?
That's the game we're playing with Earth's climate now. And the evidence says the acceleration is under way.
June 2019 -
Study predicts more long-term sea level rise from Greenland ice
January 2019 -
North American glaciers melting much faster than 10 years ago – study (The Guardian)
January 2019 -
Ocean Warming Is Accelerating Faster Than Thought, New Research Finds (New York Times)
January 2019 -
Study says seas may be rising faster than thought (Phys.org)
The media pieces noted above are far from the only pieces to this effect. Do an Internet search yourself,
and you will find many, many more. It's time to apply the brakes and get our foot off the (GHG) gas pedal.