for more than ten thousand years the average global temperature didn't change by more than one degree celsius but then humans started burning fossil fuels around here global temperatures have risen about 1 degree celsius since pre-industrial times this is what that looks like so far storms have gotten more intense wildfires are more common and ancient glaciers are melting faster and faster and that's just one degree of warming without global action the world is on track to warm at least 3 degrees celsius by 2100 this would be catastrophic that's why most scientists agree that we need to limit global warming to this range between 1. 5 and 2 degrees celsius carbon dioxide which is emitted when we burn fossil fuels accounts for most of the world's greenhouse gas emissions it's the main culprit behind climate change and to limit global warming to the degree that scientists are calling for we have to stop releasing it we have to decarbonize the us doesn't currently emit the most carbon dioxide of any country but as one of the oldest industrial powers it's emitted more carbon dioxide in total than any other country or region so america has a big role to play in decarbonizing but how is the u. s supposed to do that and is it actually possible if you want to get halfway there by 2030 you have to start now now going fast there is literally zero more time to waste dave writes about energy and climate for vox and he says the 2020 u.
s election comes with fairly clear stakes if trump is re-elected that's it like there's no chance for 1. 5 and probably all chances for two degrees are gone the united states will withdraw from the paris climate accord open up the coal mines new offshore oil and gas leasing program president trump doesn't have a climate policy and his re-election will most likely continue policies designed to boost the fossil fuel industry they'd increase carbon emissions instead of decreasing them and the effects would be felt globally you just can't have the world's second biggest economy opting out moving the opposite direction and expect the world to get there the other major candidate in the election does have a plan to address climate change and this part in particular is ambitious by 2050 the united states will be 100 clean energy economy biden has been convinced and pushed to the point that he's got a great climate plan what biden's plan doesn't get into are the details on how exactly the u. s would actually do that but there are people who have thought about what it might look like to decarbonize by 2050 and to understand that it helps to get a picture of where america's energy comes from and where it goes sorry my son nearly stepped on a snake do you want to say hi this is saul griffith he's a physicist and an engineer but this is how dave describes him probably the person who knows more about energy as it's used in the united states than any other human being a few years ago saul decided to make a model of america's energy use he ended up reading basically every available piece of data from the energy information administration department of transportation national highway transit authority census bureau of labor statistics and noaa and so we pull all of those together to build a very comprehensive picture of the u.
s energy economy that picture of the u. s energy economy it looks like this if you're just looking at the whole thing at once it just looks like a big pile of spaghetti it's hard to make sense of but it just traces energy every unit of energy how does it enter the economy how is it used throughout the economy this kind of chart is called a sankey diagram and it's easier to understand in three sections these columns here on the left are the sources of all the energy used in the u. s like natural gas coal solar wind nuclear and oil this column in the middle is what those energy sources get converted into so a lot of it becomes electricity most oil becomes the fuel we use for transportation and here you can see how much natural gas energy is being used to generate electricity versus being used directly to power things like cooking stoves and over here on the right this is where all the energy is used broken down into incredible detail like how much energy is being used to light shopping malls in the u.
s or how much energy is being used by vehicles driven for work so you start to get this incredibly detailed picture of all of the interconnections which is really really important when you do the next exercise but what happens if we decarbonize remember that carbon emissions come from the burning of fossil fuels this stuff and saul says that means that to decarbonize we just need to follow their path the first place that leads you is here with electricity and the energy we use to generate it the majority of which in the u. s comes from two kinds of fossil fuel natural gas and coal if the us wants to decarbonize it needs to stop getting electricity this way and to replace it with other decarbonized energy sources that means coal power plants gone gas power plants gone all electricity would come from renewable sources wind solar geothermal hydroelectric and biomass or nuclear energy decarbonizing the way we get electricity would be a huge investment but it would also only eliminate 20 percent of emissions and that's because electricity and energy are not exactly the same thing that doesn't solve the vehicle's emissions it doesn't solve your your heating emissions from using natural gas or fuel oil in your basement all these other parts of the economy draw their energy directly from fossil fuels like transportation we use oil for fuel and commercial and residential buildings where we use gas and oil for heat but saul says there's a kind of elegant solution to this you decarbonize these sectors by switching their energy source from here to here make all of it electric because we already have almost all the technology we need to do it heat pumps batteries electric vehicles wind turbines nuclear power plants as we know that that can work we know we can do electric cars we know we can do electric heat for nearly everything it's all in the end just about machines right we got a bunch of machines that use fossil fuel energy we need to replace them with machines that use clean electricity and so it really just comes down to a matter of industrial capacity how fast can you build machines there are some things we'd have a harder time decarbonizing air travel will rely on fossil fuels until alternative technologies get better and things like steel and concrete are really hard to manufacture without fossil fuels but if we decarbonized as much as possible with the technology that we have now it would end most of the us's carbon emissions this church shows the country's carbon emissions broken down by economic sector if electricity residential commercial and transportation were mostly decarbonized you'd have solved a lot of the problem all of this would be a huge undertaking and it needs to happen fast saul's research modeled different scenarios for the transition from fossil fuel-based machines to electric ones from a market-driven transition to carbon taxes to a much more direct and heavy-handed approach that would replace our machines with their electric counterparts very quickly and he found that because we've delayed action for so long none of these slower approaches will be enough if you went back to 2000 and started then you could just put like a modest carbon tax in place and it would have just eased us down over the course of 30 years or whatever but emissions kept rising and rising and rising so now to get where we need to go they gotta fall off a cliff and that means zero delay we're just talking about a level of industrial mobilization that none of us alive have seen it would look like what fdr did to prepare the us for war literally every single solitary fossil fuel machine that goes out of service is replaced by a clean energy alternative every furnace car you know factory name it nearly everyone is buying an electric vehicle nearly everyone is buying rooftop solar nearly every new power plant that comes online is industrial scale solar or industrial wind we need that level of effort to do a lot better than two degrees all of recorded human history has happened within an era of relative climate stability an era that's about to end but we still have control over what comes next and the global effort that'll require hinges in part on what the us decides to do america can decarbonize we have the technology to do it we have the resources the only question is whether we want to do it i have a 6 year old and 11 year old and i have to believe that's going to happen otherwise and i have to try to make that happen as far as long as possible because it's their future we're stealing by not doing it thanks for watching this episode of our 2020 election series we're focusing on the issues that matter most to you and we got this topic requested by a lot of people zach said the candidates should be talking about the steps we need to take to drastically reduce our carbon footprint and our impact on the environment jade asked what policies will be implemented during their terms to stop america from being the second largest carbon producer and oliver asked how do they plan to reduce carbon emissions to zero and on what timeline we want to know what you think the candidates should be talking about tell us at vox.
