Project Drawdown presents the Drawdown Roadmap: The Science Behind the Roadmap | Unit 2

[Music] thank you welcome to unit 2 of the drawdown roadmap video series in this video we're going to talk about the science we really need to know first before we build the drawdown roadmap the first thing I want to talk about is how climate change is caused by more than one greenhouse gas of course we've all heard that greenhouse warming climate change has caused largely by carbon dioxide emitted by fossil fuel burning that's true but there's actually a little bit more to it than that other ga

ses like methane and nitrous oxide as well as other things we do as Humanity also contribute to climate change and we need to understand all of them so let's dive in and look at it piece by piece here we see a breakdown of what causes the warming we're seeing today from its different component parts the first part and the largest is carbon dioxide emitted by burning fossil fuels the thing we've already heard about while this contributes about 62 percent of the warming we see today again this is

burning coal and oil and natural gas gasoline any of these so-called fossil fuels which releases CO2 into the atmosphere that's the biggest contributor to climate change today but it's not the only part in fact about 40 percent of climate change is caused by other stuff and we need to understand that too if we're going to truly solve the problem so one of the other ways that we cause climate change is by releasing CO2 into the atmosphere when we pour cement and make concrete this has nothing to

do with fossil fuels this is just a chemistry of cement and concrete that outgasses CO2 into the atmosphere so that's pretty important another major contributor of greenhouse gases is the CO2 we emit from land use especially deforestation burning down trees is just like burning coal or oil they're all made out of carbon just some of this is alive the other stuff is dead but they both release CO2 into the atmosphere in the same basic way about 11 percent of climate change today is caused by the C

O2 emitted from deforestation an important note 11 of the warming is caused by deforestation that's about the same amount of the total warming contributed by the entire U.S economy so here's deforestation of 11 of climate change today and here's the entire United States also about 11 today it's interesting we hear a lot about the U.S and not as much about deforestation we need to kind of keep a balance perspective and look at all the different things that together cause climate change another th

ing we have to worry about is methane an entirely different greenhouse gas from carbon dioxide methane or CH4 is also what we call natural gas so naturally part of the emissions of this stuff comes from the natural gas industry so little leaks of natural gas out of wells in the ground or pipelines that deliver natural gas to cities or even in our homes and appliances leaks of natural gas can leak into the atmosphere and cause additional climate change but methane's also caused biologically and i

t comes from Agriculture and our Farms One Source is rice fields but the biggest source here comes from animals especially cattle and dairy cows we've all heard the joke about like cow farts causing climate change well it turns out it's not cow farts it's cow burps the other end of the animal is what releases methane into the atmosphere and so the production of cattle and dairy animals and sheep and other livestock also contribute quite a bit of methane to the atmosphere adding to climate change

we also have a gas we don't hear very much about called nitrous oxide or n2o this is another powerful greenhouse gas that's largely driven by fertilizer use and using manure in farms around the world it turns out that nitrogen in fertilizers and manure sometimes combines with air and water in the soil and outgasses as nitrous oxide adding more to even climate change and then we have a whole family of gases called f gases or fluorinated gases which are typically used as things like refrigerants

or other industrial purposes out there and when these gases leak out of like an air conditioner or refrigerator or freezer or something like that they build up in the atmosphere too contributing yet a little bit more to climate change so here's the big picture we have multiple gases CO2 methane nitrous oxide fluorinated gases and a few more all driven by different things many related to energy some related to land use and Agriculture and some related to the use of specific materials like cement

and refrigerants and we have to think about all of these things if we're going to truly tackle climate change in a comprehensive way the other thing we need to think about is that each Gas Works a little bit differently in particular methane let's talk about that one for a moment if we think about our emissions of greenhouse gases today and how they're going to warm the atmosphere in the future methane will warm The Atmosphere by about 16 of the total warming over the next hundred years but if w

e look over the next 20 years in particular that amount of warming almost doubles in significance methane is a powerful greenhouse gas but it doesn't live in the atmosphere very long so it warms a lot up front and then goes away quickly so the near-term methane is a very important part of climate change but out in the future maybe 100 to 300 years from now carbon dioxide becomes more important because it lasts longer in the atmosphere this is why we have to look at each gas kind of differently n

ot only about where it comes from but how it works in the atmosphere and what it does to the future of our planet the other thing we have to consider is not only the different gases and the chemistry involved but also the different economic sectors that contribute them to the atmosphere and where we need to start our actions so if we think about the things that we do that cause climate change the most significant might be making electricity about a quarter of climate change today is caused by bu

rning fossil fuels coal and natural gas in particular to make electricity that's 25 percent of the total problem but food Agriculture and land use is also roughly about a quarter of what causes climate change isn't it interesting electricity and food are about equal and causing climate change in the world and yet we hear a lot more about electricity than we do food but it turns out food is a major contributor to climate change and we've got to think about that one too then we have industrial sou

rces things like making cement steel making plastic processing waste around the world all those kinds of things that's also a major contributor to climate change at about 21 percent then we have transportation things like cars trucks boats trains airplanes all of that stuff that we used to get us and our Goods around the world that's about 14 of the problem then we have buildings which in addition to the electricity they use and the materials they're made from emit even more greenhouse gases ano

ther six percent or so from things like furnaces hot water heaters boilers leaking air conditioners basically the stuff in the basement of your building that's contributing too but if you think about electricity used by buildings the building's own emissions and then the stuff the buildings are made from that overall built environment is a huge contributor to the climate change problem and then we have the final 10 percent which mainly is tied to things like processing oil and refining oil into

its useful components or leaks of natural gas what are called fugitive emissions and gas flaring so most of that's tied up in the kind of energy industry itself but the first 90 percent of climate change is caused by five activities on this planet making electricity making food industry transportation and buildings just those five things are ninety percent of what causes climate change and we can dig into each of these and look in more detail in fact the science is pretty clear that we can see l

ots of detail about where we use different things and how each contributes to climate change this graph here breaks down the global sources of greenhouse gases in even more detail so we can see all the different things we need to do to truly address climate change around the world the next thing we need to do besides describing the chemistry and the sources of greenhouse gases is understand better what's going to control their future levels in the atmosphere because the level of greenhouse gases

is really what controls the warming the higher the level of gas the bigger the warming is going to be so what is controlling that in the future that's another thing we need to think about as we move forward well let's imagine the atmosphere filled with greenhouse gases represented by these little clouds right here I already told you about this these sources of gases that's the stuff we do that puts those gases in the atmosphere like burning coal burning down trees you know belching cows all tha

t kind of stuff but another part of the equation is what we call the sinks of greenhouse gases sources put it in the air sinks take it back out well it turns out there are some natural background sinks on this planet today that remove some of our greenhouse gases just through natural processes these sinks are happening today mainly in the world's forest and in our oceans now normally forest and oceans are in kind of a chemical equilibrium they emit as much greenhouse gas as they absorb so there

shouldn't be a large persistent net sink of greenhouse gases but there is right now for carbon dioxide why well it turns out it's because CO2 levels in the air are rising causing kind of a fertilization effect the world's trees in the world's oceans are now absorbing more CO2 because there's much more of it in the air than they're used to and that so-called kind of fertilization effect is driving sinks of carbon in our forest in our oceans above and beyond what's normal for our planet and that's

removing about half of the carbon dioxide emissions we're putting in the air every year thank goodness because if that weren't true global warming would be a lot worse today than it has been now above and beyond these natural sinks of carbon that are happening right now we humans could maybe if we're clever add even more and we call these anthropogenic sinks that's just a fancy word for human caused sinks these could be things that we do on land like planting trees or in the oceans like farming

kelp or maybe with machines that actually sucks CO2 out of the atmosphere and pump it underground where it can't cause further harm these so-called anthropogenic sinks are usually called carbon removal projects that is kind of an additional project that we do as people that removes carbon out of the atmosphere and locks it up in trees and oceans and maybe underground with machines well these are really important but right now we have to ask some tough questions about carbon removal projects bec

ause a lot of them don't really exist at a meaningful scale today they're very very small so before we bet the planet on them we have to ask ourselves are these real are they really going to show up are these things actually going to work and sometimes that's still an open question the other thing we have to acknowledge is that some of them are going to take time to work like planting trees or farming differently sounds great but it can take years and decades for trees to grow and soils to chang

e and accumulate carbon in biomass and in the soil so it won't happen right away it may be delayed by decades if we don't watch ourselves another thing we have to think about is What's called the permanence of carbon removal if we take carbon dioxide out of the atmosphere and stick it in a tree that sounds great but what if the tree were cut down or maybe Burns in a forest fire in the future that would instantly vaporize that carbon back into the atmosphere undoing the entire carbon removal proj

ect right there so we have to be careful about the permanence of carbon removal make sure it's really locked away for good and finally we have to make sure carbon removal is verifiable that we know how much we removed and that we can use that effectively into the future and sometimes the bookkeeping and accounting for this can be a little bit slippery so we have to think about climate change by looking at all of these different levers the sources the natural sinks and then human-caused carbon re

moval each lever that we can pull works pretty differently the sources of pollution going in Nature's sinks coming out and then of course carbon removal after that how do they work and which ones should we pull in different ways well first of all cutting the sources is key there's no way around it this is job number one two and three is cut the pollution from the beginning that's the best way to solve this problem beyond that we can look at natural sinks of carbon and think about those but natur

al sinks are helpful but they're likely to decline in the future as CO2 levels start to stabilize so will these natural sinks eventually slow down as well so they're there now but they may not always be there at the same strength in the future and we have to be careful about depending too much on natural sinks and finally carbon removal could be incredibly helpful but right now it's very small and it's taken years to even get here so how much longer will take for those to scale and how much can

we count on well those are still real questions that deserve answers and we don't have the full answers to that today as we think about those two parts of science we can now look at the paths that help us look at where we can stop climate change in the future and that's what I want to show you now this graph here talks about the emissions of greenhouse gases over the last few decades that red line shows all of the emissions of all those greenhouse gases of carbon dioxide methane and everything e

lse as a single curve we've been riding up that red curve and today we're at the Red Dot here in the early 2020s if we were to continue on this path of increasing the level of emissions each year we might be expected to go up that dotted line just extrapolating the last few decades into the future but that would be a disaster in fact what we really need to do is just the opposite not only not increase emissions we've got to cut them dramatically in the next few decades it would be best if we cut

our emissions a lot right now in the 2020s and early 2030s and hopefully we can cut them by maybe 40 to 50 percent in the next 10 to 15 years if we did that that would keep us on path for what are called the Paris Accords that would limit the warming of our planet to 1.5 degrees up to maybe two degrees better though closer to 1.5 if we follow that curve that would keep us on target for a 1.5 degree World which is probably the best we can hope for at this point so if we cut emissions dramaticall

y in the first decade or so and keep cutting them in the 2030s and keep cutting again in the 2040s we've done a lot of the work we need to do but is it realistic to cut all greenhouse gases completely in every economic sector in every Source in every country in the world by 2050 well I'd love for that to be true but maybe it won't be so we might not be able to depend on emissions going completely to zero not a hundred percent but maybe we can get it down to 90 percent Cuts let's see but if we ca

n't cut everything it's probably necessary for us to balance that last little bit of pollution with what we might grow as carbon removal now again carbon removal today is very very small even if we multiplied all the carbon removal on Earth today by a million it would just barely show up on this graph it's got that much more to scale before it's a significant player but using new technologies and new Investments we can probably scale this technology into the future but it's going to take a littl

e time but the hope is in the coming decade or two we'll get to the kind of gigaton scale of carbon removal and by mid-century be able to grow that enough to remove the last little bit of emissions we couldn't get rid of in the first place but as you can see the big job is cut the pollution and then a little bit of removing what we couldn't at the end when we do both of those things cutting emissions dramatically and removing the last a little bit thus will reach what's called Net Zero Net Zero

is the moment when we stop climate change from getting any worse that's when pollution basically stops accumulating we're only emitting a little bit and we remove it through carbon removal projects and then the warming of the planet will stop at that point the sooner we get to Net Zero the sooner we can stop the warming and the sooner we can stop the accelerating damages to our planet so what that requires again is Big emissions Cuts now there's just no way around that we've got to cut emissions

dramatically as soon as we possibly can in addition we're going to have to take some time to allow for limited carbon removal to grow by mid-century to remove the last little bits of pollution and together they can solve the problem but one of the things we should learn along the way that a lot of people seem to mistake here is the importance of time I want to tell you about this concept called the time value of carbon it's a little bit like the time value of money you might have heard about fo

r example if you want to retire when you're older everybody tells you you should start saving early maybe in your 20s and 30s and do a little bit over time because it will accumulate that's because saving money is the area under the curve it's the total amount of stuff that you do that matters not just how much you save every month but the total number of months you do it well the same thing's true with climate change it turns out actions we take now accumulating over time can have the biggest i

mpact so when we talk about cutting emissions to the 2020s we can remove this much for carbon from being in the atmosphere that whole blue area is the carbon prevented from going in the atmosphere but the things we do in the 2020s keep on accumulating in the 2030s like this and the 2040s like that so what's kind of amazing here is the actions we take early in the 2020s pay off the most handsomely because they have so long to accumulate between now and the 2050s amazingly about three quarters of

what we need to do to stop climate change are emissions Cuts just in the 2020s and early 2030s so early action pays off and keeps on paying in the future but of course we'll keep cutting emissions in the 2030s and that's what this can prevent from going in the atmosphere but by the 2040s while new technologies and new ways of cutting emissions will be very welcome and needed there's just less time for them to work so it's a mathematical kind of constraint on the kinds of solutions we can use ear

ly solutions that are here now with existing technology are automatically way more powerful than Solutions deployed later with new technologies so it's you know it's very tempting and kind of sexy and interesting to wait for new high-tech solutions to climate change but if we wait too long they just don't have a lot of time to work and they're not going to be as helpful in stopping climate change as the low-tech stuff we have right now in our hands so that's why at project drawdown we often say

time is more important than Tech the other thing we have to think about is carbon removal will be important in the future but it's growing from a very small number and will take years to scale that's why when you accumulate its total impact it's really not all that large when you look at the total play out of everything and all together in this scenario cutting emissions actually does about 94 percent of the work to stop climate change and cutting emissions in the next decade or so that's doing

75 percent of the work because it has three decades with which to accumulate removing carbon will be really important too but overall it does more like six percent of the total work to stop climate change the big story here is again cutting emissions is critical and early action is key so with all that we've built a little bit of scientific knowledge that we can use to build this road map that is the kind of science that will guide our actions into the future because now we not only know what to

do like what Solutions work and which ones are best we also know how to do them where to do them and when and this gives us a more comprehensive perspective to build the drawdown road map which I'll talk about in the next video [Music] thank you foreign