Warming Thoughts #2—Gigaton—the most important term to really grasp if you want to understand the magnitude of the global warming problem

James F. Lavin, CEO Electron Storage, Inc.

Virtually every discussion of global warming has a reference to the number of gigatons (Gt) of CO2 being emitted annually, around 35Gt, or gigatons of CO2 and other greenhouse gas equivalents, around 50Gt, and the need to get emissions down to net zero by 2050.  Net zero assumes we are capturing and permanently disposing (sequestering) enough CO2 emissions to equal whatever CO2 equivalent emissions are still occurring by 2050.  This is generally assumed to be around 10 gigatons/year.  Since to date we have made no progress on reducing CO2 emissions, we may need a lot more gigatons of CO2 to be sequestered to meet that goal.  Without a real grasp on the magnitude of a gigaton, it is impossible to understand the true magnitude of the changes required to make the transition away from fossil fuels possible, how much needs to be removed, and how inconsequential are many of the touted green successes.

A gigaton is a billion metric tons (a metric ton is equal to 2,204 lbs or 1,000 kilograms).  The weight of a cube of water one meter on a side is a metric ton.  A billion is 1000 x 1000 x 1000, so a cube of water a kilometer on a side is a gigaton.  That is still hard to relate to.  Since I will refer several times in this series to Robert Moses, the master builder of New York as portrayed by Robert Caro in “The Power Broker”, and since I live in New York City, let start with an example from his time, the Empire State Building.  The Empire State Building, all 102 stories weighs only 331,000 tons, so you would need 3,000 of them to equal 1 gigaton.  Since there are around 7,000 buildings over 35 meters high in Manhattan, and it is a safe bet that the average is a lot less than half the size of the Empire State Building, the weight of all of the buildings in Manhattan is probably around a gigaton.

Let’s try something we all are familiar with, cars.  If we assume the average car is around 2 tons, and US auto production around 17 million vehicles, we still don’t get anywhere near a gigaton, we get to only 34,000,000 tons.  You need around 30x total US vehicle production to get to a gigaton of cars.  Sticking with cars, if the average length is 5 meters and you put them end to end from NY to LA (4,500,000 meters), you would need to do this more than 500 times to make a gigaton of cars. 

A PBS NOVA series had a wonderful graphic.  Imagine creating a block of coal to fill the entire Washington Mall from the Capital to the Lincoln monument up the height of the Washington Monument.  A gigaton---not even close.  Fill it 10x the height of the Washington Monument and we get to a gigaton. 

A gigaton is not something to be thrown around lightly, and neither is the infrastructure to handle a gigaton.     

The world does deal in gigaton scales.  World coal mining is approximately 8 gigatons.  The most produced substance on earth is cement, and we produce around 4.4 gigatons of cement (releasing around 4 gigatons of CO2 in the process). We produce around 2 gigatons of steel every year.  Global mining is probably on the order of 40 gigatons a year.  Oil production, pre-Covid, was running around 100 million barrels a day, at 20 kilograms per barrel times 365 days; around .75 gigatons. 

The infrastructure of the entire fossil fuel industry, oil, natural gas, natural gas liquids, biofuels and oil combined, moves perhaps 3.5 gigatons annually.  In short, all the infrastructure of pipelines, refineries, tankers, compressor stations, LNG ships, and storage tanks handles between 1/3 and and 1/5th of the 10-15 gigatons of CO2 that has to be handled—under the most conservative assumptions, to achieve the needed level of CO2 negative emissions.

CO2 has to be captured and compressed or liquified to even enter the system that can transport and dispose of it.  Think of a large enclosed stadium, like the New Orleans Superdome which encloses a 13-million-liter volume.  It contains one single ton of CO2.  We need to separate the CO2 out from the air and do it a billion times—for a single gigaton.  If you are still struggling with conceptualizing a billion, a billion one-dollar bills would stack around 68 miles high. 

To mitigate climate change, we need to work at gigaton scales.  The vast majority of projects and proposals under discussion or announced to applause deal with changes on the order of hundreds, or thousands of tons, or even hundreds of thousands of tons.  For example, making public housing energy efficient is a perfectly nice goal and an expensive one, it’s just irrelevant to seriously tackling global warming.  New York City’s very aggressive, very expensive, and very labor-intensive CO2 reduction mandates, would, in the best case, result in a reduction by 2030 of 25 megatons/yr emissions, ie in 40 years it would reduce emissions by a gigaton.  When you are dealing with gigatons, cost matters, time matters, and marginal costs matter so don’t do low impact,difficult, expensive things first.