We were admonished on the blog by “Otway1” for our “seemingly deliberate scientific ignorance” because “[t]he evidence for anthropogenic (manmade) global warming driving climate change is overwhelming.”
I asked him for “one measured signal that suggests global warming is a problem.”
He replied that he was “spoilt for choice but try this one: NASA tells us Antarctica and Greenland are now losing ice 6 times faster than they did 40 years ago” and “that if all the land ice melted it would raise sea levels, not "by a few cm at top" … but over 60 metres”.
It’s true that earlier this year NASA headlined a press release, “Greenland, Antarctica Melting Six Times Faster Than in the 1990s”.
Let's start with the economic calculation behind the headline.
Politicians love to scare. It makes them important and enables them to take more money and greater control. Scientists love to scare: it makes for bigger budgets and increased research. And journalists love to scare: it grabs readers and hence advertising dollars.
The actual truth is that the ice loss is not news. And certainly is nothing to be alarmed about.
As my ten year old explains: of course ice is melting, we are coming out of one of Earth's many ice ages. Twenty thousand years ago our backyard was a glacier. It's now grass.
Ice Ages come and go: there’s no news or alarm in that. And yes, sea levels likewise rise and fall. Twenty thousand years ago the South and North Islands were joined.
The melt is not a straight line. For example, we had the Medieval Warm Period and the Little Ice Age, all well before industrialisation.
Over the last 20,000 years the ice has accreted and diminished many times over and often in different directions in different parts of the world.
Ice Melting is not a signal that global warming is a problem.
But maybe the melting six times faster than 30 years ago is cause for alarm? Nope. It wasn’t melting much 30 years ago and six times "not much" is still "not much".
The NASA Press Release gives the numbers:
The team calculated that the two ice sheets together lost 81 billion tons per year in the 1990s, compared with 475 billion tons of ice per year in the 2010s - a sixfold increase. All total, Greenland and Antarctica have lost 6.4 trillion tons of ice since the 1990s.
My ten year old said that sounds a lot but thought some more and asked how much ice in total?
She and I did the sums.
“Otway1” tells us that all the Antarctic ice melting would raise sea levels 60 metres. That’s close enough to the best estimates.
The NASA Press Release explains the consequence of losing 6.4 trillion tons over 30 years:
The resulting meltwater boosted global sea levels by 0.7 inches (17.8 millimeters).
My ten year old did the arithmetic: so over 30 years Greenland and Antarctica have lost three hundredth of one percent of their total ice?
As best as we can estimate it.
That's 17.8 mm as a percentage of 60 m.
It's a nothing. It's certainly not a signal of anything out of the ordinary.
This one example illustrates how the government-science-media monster works: scary headlines that a ten year old can work out but endlessly repeated as true at school and in the media until we uncritically accept it as true.
That's how propaganda works.
And sadly that's what much of our news, our science and our government has become.