OK #energytwitter: This week's nerd thread.

Why climate change is real, and man made. And why you should treat anyone who insists otherwise with the same respect you treat someone who insists that gravity is also a left-wing conspiracy. (Warning: this thread contains science.) https://twitter.com/SeanCasten/status/1293905402686574592

1/ First, you gotta understand the 1st law of thermodynamics. Energy can neither be created nor destroyed. If you put 5 1 lb weights in a bag, the bag will weigh 5 lbs. If you put 500 1 Btu pieces of energy in a bag, the bag will contain 500 Btus.

2/ Energy can however be converted. You can take electric energy, put it through a resistor and make heat. You can take chemical energy from gasoline and turn it into mechanical power in your car engine. But the energy that comes out = the energy you put in.

3/ So way back in 1820, Joseph Fourier, armed with the 1st law had a math problem. He measured the energy coming from the sun to the earth (as light) and estimated how warm the earth should be when that light was converted to heat. His math said the earth should be ~0F.

4/ The moon, which is the same distance from the sun is that temperature. But the earth was closer to 57F. How come we are so much warmer than the moon?

5/ The answer, it turned out was CO2. In 1908, Svante Arrhenius figured out that CO2 (and water vapor, and methane) acts like a blanket around the earth. But it's a weird blanket.

6/ Weird because while those gases are invisible to light, they absorb heat. So when that light hits the earth and gets converted into heat (remember that 1st law), the heat bounces back and gets trapped by those gases. Ergo, the "greenhouse effect".

7/ Arrhenius then did the math and calculated that if the CO2 content in the atmosphere were 50% lower, the earth would be 4C cooler. And if were doubled, the earth would be 4C warmer.

8/ This was in 1908, mind you. 5 years after the Wright Brothers flew at Kitty Hawk. 20 years before the TV was invented. 40 years before the transistor was invented. For all practical purposes, the science of climate change has been settled since that date.

9/ Back in 1820 when Fourier first identified this math problem, the atmospheric CO2 concentration was 284 ppm, which was roughly where it had been for the prior 100,000 years, and that CO2 was the result of volcanoes and breathing animals.

10/ By 1908, CO2 was up to 299 ppm. 311 ppm by 1950. By the time I was born in 1971 it was up to 326. Today it's over 410 ppm. That 100 year spike is totally ahistorical, and totally due to our species.

11/ Remember, prior to Watt inventing the steam engine in 1776, our species access to power was limited to our access to muscles. But the steam engine gave us concentrated power, first was we converted wood and peat to mechanical power, and then from coal.

12/ William Drake tapped the first oil well in Titusville PA in 1859. The access to all that concentrated energy has massively increased our standard of living. (Amazing what you can do when you don't have to churn butter all day).

13/ But by depending on fossil fuel combustion to provide that energy, we took carbon that had been locked underground and barfed it into the atmosphere. That is why the CO2 concentrations have spiked over the last 150 years.

14/ And Arrhenius and Fourier's math still holds up. Put more CO2 in the atmosphere and the temperature goes up. This is why we call it man-made global warming.

15/ As an aside, can you imagine asking an ethics review board to allow you to do an experiment where you test Arrhenius and Fourier's hypothesis by injecting massive CO2 into the atmosphere and seeing if it gets hotter? That's essentially what we've done.

16/ Also: carbon normally has a molecular weight of 12, but there is an isotope at 13. Plants prefer C12 when they photosynthesize. CO2 calculated in ancient ice cores shows a shift to more C12 post-industrial revolution - because we were burning old plants (aka, fossil fuel)

17/ So we KNOW that our species burned the carbon that made the CO2 that made the temperature go up. And we know that Arrhenius - and Nelly - were right. It's getting hot in here.

18/ And we keep emitting. We are adding almost 3 million pounds of new CO2 into the atmosphere every SECOND. That works out to the energy addition of 4 Hiroshima class nuclear weapons. Every second.

19/ But that 1st law still holds. We took chemical energy stored in the earth and converted it into heat energy. The heat doesn't go away. It melts ice. Heats the air. Heats oceans. Fuels hurricanes. It makes our entire planet a lot more volatile and dangerous.

20/ If you care about national security, this should scare you because climate destabilization (see: North Africa) destabilizes governments and creates refugee crises and large numbers of unemployed young men. The stuff of which wars are made.

21/ If you care about inter-generational equity this should scare you WAY more than deficits because the mess you are leaving our kids to clean up there is no way to inflate this problem away, or find an understanding lender to write down.

22/ But it's also a great opportunity. Because the standard of living we all depend on doesn't depend on fossil fuel. It depends on access to USEFUL energy. Transportation. Heating. Cooling. Light. And we can make all those forms of energy without burning fossil fuel.

23/ And if you don't burn fossil fuel, you don't have to pay for it either. The sun, the wind, the tides... those are all free. Which means that we have a massive ECONOMIC opportunity to fix a massive climate problem.

24/ The science is settled, and has been for a century. The opportunity is before us. Give the deniers a tinfoil hat and a padded room if you must. But more importantly, let's get to work. /fin

One postscript: I owe Charlie Bayless a huge debt for teaching me how to explain this stuff. Much of this is a blatant plagarism of stuff he's told me through the years. He's not on Twitter, but worth reading everything he's ever written on energy & climate.