Carbon Intensity

Emissions

 

The total emissions of carbon pollution from human sources for 2011 was about 50 gigatons. Terrestrial GHG (Green House Gas) sinks took up about 20 gigatons. Therefore, human processes in 2011 had net emissions about 30 gigatons (30,000,000,000 tons) of carbon pollution. So, worldwide, about 40% of carbon pollution is being sequestered by sinks. You ask, “Is that good news?”

No, but it could be worse.

Also called CO₂, CO₂e, or GHG gases, carbon pollution is now being addressed by most nations on the planet. Many nations tout their reductions in CO₂ emissions on a year over year basis. For example, Country-X has reduced its annual CO₂ emissions 15% below 2005 levels–something to be proud of, right? How does that 15% reduction in yearly emissions correlate to the increasing concentration of CO₂ (a key GHG contributor) in the atmosphere? Or, to ask the question in another way: If Country-X reduces its CO₂ emissions in 2013 to 15% below 2005 levels, does that mean we have made a 15% dent in the carbon pollution problem?

No.

Any decrease in CO₂ concentration in the atmosphere, or any increase, is the result of two items: CO₂ emissions and CO₂ sinks. If we have too much in the way of emissions and they swamp the terrestrial sinks–the CO₂ concentrations in the atmosphere will increase. If CO₂ sinks do not outweigh, (or sequestration systems like burying CO₂ in the ground) do not outweigh emissions, the atmospheric concentrations increase. If, on the other hand, emissions are less than the capacity of terrestrial GHG sinks, then the concentration of GHGs (like CO₂) in the atmosphere decreases. So the name of the game is making our emissions less and our mitigating systems, like the carbon sinks more–easy right?

No.

The way we measure the concentration of CO₂ in the atmosphere is by the amount of CO₂ in a given volume of the atmosphere. For most of the last few hundred thousand years, that measurement has varied from 190 to 290. We crossed 400 last month. The year before, the number was in the 398 area. “Hang on, wait.” You retort. “If we have reduced our emissions, how could the carbon pollution number go up? Doesn’t that 15% mean anything?”

Yes, but not what you think.

We are 30 gigatons over budget, and because emissions are not the same as atmospheric concentrations, emissions act like effluent from a faucet into a basin. A big human faucet adds more stuff (GHGs) to the basin (atmosphere). A smaller faucet adds less stuff. A faucet that adds zero net stuff is carbon neutral. The human carbon faucet is 30,000,000,000 tons too much. It needs to be zero–quickly. “So where does that 15% reduction in emissions fit in?” You ask suspiciously.

You’re not going to like the answer…Alright, ready? Sure?

Okay. To reverse anthropogenic forcing of the radiative balance (human induced climate change) that 30 gigaton number has to go negative. To keep it from getting worse, fast, the balance between sinks and emission must level out…To zero. That means we need to be at zero net output of carbon emissions and their equivalent, rather than 30 gigatons (30,000,000,000 tons). The 15% reduction means that without it, the 30 gigatons of emissions would be larger. Any positive emissions number feeds the concentration of GHGs making it larger. Any negative emissions number lowers our risk. We are way over budget. Worldwide, we are dumping a net amount of 30,000,000,000 tons of carbon pollution into the atmosphere.

This is the reason some seek an energy/economic system that is carbon neutral–to get to zero net emissions. Zero means no increase in CO₂ emissions year over year. That net zero number also means the concentration of CO₂ (400) doesn’t rise. A negative CO₂ emissions number reduces the concentration of CO₂ down from 400. A positive adds to it. Remember that 400 is the current concentration of CO₂ in the atmosphere. Yearly increases in CO₂ feed it. Yearly decreases in CO₂ starve it. The larger the net CO₂ emissions (30,000,000,000 tons), the faster the concentration of carbon pollution (400) will rise. Most importantly, any increase in CO₂ emissions will add to the problem–let alone another 30,000,000,000 ton increase next year. “So,” you ask. “How fast will it rise? And by the way, how long will the CO₂ stay in the atmosphere?”

With worldwide current net emissions at 30 gigatons of CO₂e, that 400 number will rise by about 1.5 – 2 per year.

If the US were to go carbon neutral–that is zero net emissions of carbon pollution–rather than the approximate 6.7 gigatons of CO₂e we put out now, the rate of increase would only  change by 1/5 or so. For example: instead of a 1.5 increase in carbon pollution concentration per year, the change would be about 1.2 or so. The number would still increment–every year.

Frustrating, huh?

This is an insight into why negotiators stay awake at night trying to negotiate CO₂e emission treaties. If the US goes hog-wild to reduce emissions and the rest of the world does not, our efforts are minimized–say our negotiators. To be clear, I find the argument valid, but shortsighted and suicidal. We must lead on this issue of climate change (anthropogenic forcing of the radiative balance), not follow.

The next logical question: “When does that 400 number become dangerous?” If you didn’t like the other answers, you’ll hate this one:

Anything above 300 is dangerous.

Then there is that question of, “How long does CO₂ persist in atmosphere before it breaks down?”

About 60 years–are we screwed or what?

This all means that when a nation touts a net reduction of 15% below 2005 levels it really means our carbon pollution output is not rising as fast as it once was. This is a major accomplishment–but way too little to get ahead of the curve on the problem. Scary right?

Yup. We need to do something about this, quickly.

For science, the core issue of climate change was whether there were enough sinks, or other mitigating systems, to stop the results of a rapid increase in retained energy by the planet (climate change, anthropogenic forcing of the radiative balance). When it was determined emissions would dwarf the sinks, science concluded we have a crisis. This was back in the 1990s. “Why wasn’t anything done?” You ask.

 The issue was, and is, political will. That means getting the layperson to get behind solving the problem–with all of the sacrifices a solution entails. For example, all of our energy producing systems generates GHGs–either in the manufacturing process or through their use of fossil fuels. Are you willing to cut your energy usage by 60% plus? Secondly, it is a political nightmare to foster significant change that will damage powerful allied entrenched interests. Third, rapid political change on the issue of the climate will hurt everyone–but doing nothing is lethal to our civilization. Worse, the clock is ticking. At some point in the future (The Tipping Point), we will be powerless to halt damage to our species from the changing climate.

At this juncture, many see human induced climate change as the major subject of our time. Sadly, many others do not understand the extent of the crisis. Unchecked, the changing climate will devastate our economy in the near future. A little further out in the future, worldwide GHG emissions–at their current rates–will be deadly to our species.

It is time for clarity, leadership, and courage.