Now What?

LARGE_KC400_NowWhat_BU003063So we’ve reached 400 ppm.…  Now what happens?  

In May 2013, for the first time since accurate measurements of atmospheric carbon dioxide amounts began in 1958, a daily value of 400 parts per million (ppm) was observed at Mauna Loa in Hawaii, the site of the longest continuous observational CO2 record. The Keeling Curve, the famous graph of monthly average CO2 values established at Scripps Institution of Oceanography, UC San Diego, soon will decline as it does every summer but next year it will rise higher still. The annual growth rate of the Keeling Curve has been roughly 2 ppm every year averaged over the last decade, and that growth rate gets faster as well every decade because human emissions of CO2 each year have been more than the previous 10-year span.  At this pace, we will reach 450 ppm well before year 2038.

Is it dangerous for CO2 levels to be this high? 

We know that excess CO2 is contributing to the human-caused increase in the greenhouse effect and is thus warming the planet.  There is some uncertainty as to just how much warming would be associated with any given amount of atmospheric CO2, and there is considerable subjectivity in deciding what level of warming should be considered dangerous. Many governments throughout the world have agreed that global warming should be limited to no more than 2º C (3.6º F) above the average pre-industrial temperatures of the 1800s. A recent authoritative report concluded that a level of CO2 between 370 and 540 ppm has a 66 percent probability of keeping the world within this 2º C limit on warming, with a best estimate of 430 ppm. There is also a time lag for the global temperature to catch up with the CO2 that humans have already added to the atmosphere, so temperatures will continue to rise for many years after the atmospheric CO2 amount is stabilized.  Plus, we aren’t sure that limiting warming to 2°C is “safe,” at least not for everyone on the planet.

What would it take to stop the Keeling Curve from going up further?

It is a well-established fact that atmospheric CO2 is rising at roughly 55 percent of the rate expected from fossil-fuel emissions.  From this fact, we know that to stop CO2 in its tracks at 400ppm, we’d need to cut fossil-fuel emissions immediately by 55 percent.  At that point, the remaining emissions would be exactly counteracted by natural “sinks” that are removing CO2 from the atmosphere. The main sinks are the oceans, which absorb CO2 as it dissolves in seawater, and land plants, which convert the carbon in CO2 into relatively long-lived storage pools such as wood or soil organic matter. These sinks are acting like a sponge that is soaking up some of the extra CO2. Over time these sinks would slowly saturate as they come into balance with the 400 ppm in the air, and additional cuts would then be needed to match the decreasing sink capacities.  By 2060, we’d have to cut emissions to below 20 percent of current levels.

An immediate cut in fossil-fuel emissions by 55 percent is clearly not even remotely possible, so CO2 will continue its relentless rise.  Keeping CO2 below 450 ppm will also be very difficult, as this will require immediately leveling off of fossil fuel emissions and then cutting emissions to below 30 percent of present levels over the next 50 years or so.  If nothing is done to reduce the dependence on fossil fuels, CO2 could keep rising for centuries, depending on the amount of coal, natural gas, oil, and any new forms of fossil fuels that are extractable. By some estimates, the ultimate resource of fossil fuels may be large enough that CO2 will rise as high as 1,600 ppm before fossil fuels are fully depleted.  This would be sufficient to cause the world to warm between 4 to 10° C (7 to 18° F) with unimaginable consequences.

– Lisa Welp is an assistant project scientist in the Scripps CO2 Research Group

– Ralph Keeling is a professor of geochemistry and leads the Scripps CO2 Research Group


14 thoughts on “Now What?”

  1. – Photo tricks : Propaganda or Science ? Photos of steam coming out of chimney’s photographed with lighting set to make it look dirty. The link to this page seems uses that trick . Then on this page you use an oil rig flaring, which is necessary at some parts of the operation for safety reasons.
    – How can you expect us to take the SCIENCE seriously when you use such tricks ?
    – It damages science itself when PR people try to stretch it beyond what has been properly VALIDATED. ..love Science

    1. Hi Stew,

      Agree that the “artistic license” is a little “unscientific” but how else can we convey the the emission of colourless CO2 from a chimney? Fair point though…..

      As for flaring – don’t get me started! Total flaring by the oil and gas industry is equivalent to 30% of all gas consumption in the EU – rather than being largely for “safety” reasons this flaring occurs because it is uneconomic to market the co-gas produced with the oil and so it is burned off in an act of unprecedented environmental irresponsibility.

      The oil and gas sector has been promising for years to end flaring and they haven’t!

      I too LOVE SCIENCE and I also LOVE FACTS. Lets not hide flaring behinds this safety excuse and expose the practice for what it really is!



  2. Niall, firstly sorry, I did not check the flaring data .. If I were you I would double check that 30% It breaks the “Too good/bad to be true rule“, (yes it is in Wikipedia, but I expect someone has mixed units up or decimal points somewhere.. but I cannot quickly find real data and no one is paying me for my time.
    – (the idea that gas companies are just burning money away sounds like ridiculous conspiracy)
    – pics of chimney’s or any other way are POLITICAL so don’t belong in a science report, do they ?someone else might show a volcano or CO2 rising off the ocean

  3. – Ah OK that phrase says “WORLD flaring is equivalent to 30% of EU natural gas consumption”
    I think that is tricky spin – actually
    2010 world production 3,359
    2011 world flaring 150 (billion cubic meteres)..I make that 4.5%

  4. Hi Stew.

    Appreciate you are doubtful about Wikipedia – how about another more scientific sources:

    Another piece of data on flaring: taken from “Trends in global CO2 emissions; 2012 Report” available at http://edgar.jrc.ec.europa.eu/CO2REPORT2012.pdf – see page 15/16

    “The global CO2 emissions of about 250 million tonnes from flaring of unused gas during oil production – comparable in magnitude with total CO2 emissions in a medium-sized country such as Spain – did not significantly change in 2011, after a steady decrease by about a quarter since 2003.”….

    By the way the UK’s emissions are 750 million tons of CO2 so these emissions are about 1/3rd my own countries…… so what about the US?…….

    “However, satellite information shows that flaring emissions in the United States are on the rise, with a steep increase of 50% in 2011, making the country now the fifth largest gas flaring country. The main cause of the increase is the country’s recent massive increase in the use of hydraulic fracturing, or fracking, for shale oil production and the ensuing flaring of co-produced gas (Nicholson, 2012); in particular, in North Dakota and Texas.”

    The key point I am trying to make – rather than split hairs over the numbers – is that flaring is primarily an economic decision made by an oil company who does not wish to market (or capture and re-inject) the co-gas. As the study says:

    “When natural gas is co-produced during conventional or unconventional oil production and cannot be marketed, this ‘associated’ gas is either vented or flared. Venting or flaring occurs in areas that are remote from market demand and from gas transport infrastructure.”

    Yes SOMETIMES flaring is needed for safety reasons, but the principal reason is economic – hence my determination that this is understood so that companies cannot hide behind safety when they are polluting.

    Of course this fact is POLITICAL in that people who are aware of this might lobby for change. It doesn’t mean that this is not also SCIENTIFIC.



  5. Niall, 1. my gas industry expert is travelling has promised to get back to me in a few days time
    2. you are STILL comparing global with regional, why not just quote global for both ?

  6. OK he is an expert in oil field production ..”overall I’d say 5-20%” ..but does give interesting notes on the practicalities.
    Sometimes economic – when the value of gas produced won’t cover cost of building a pipeline.
    In SOUTH EAST ASIA or EASTERN EUROPE. Where there’s little or no legislation concerning flaring/CO2 emissions.
    1. There can be screwups when gas proportion turns out to be more than expected (maybe 5-20% of the gas, for short period 3-6 months.) – As time passes you push more gas underground to push up the oil, then flaring is Probably less than 5%
    2. Brownfielding : When new well is connected to facility, so you get a bottleneck “one time I was shocked to see for MANY YEARS it seemed they were flaring around 5% -10%”

    IN CANDA & BRAZIL his experience is that “The laws are very strict and they get their asses fined for flaring” “In general, flaring only takes place during upsets (say a compressor train trips), or in some cases during facility start up.” cos they use the gas to power their operation : pressurising to enhance oil recovery and to sweep the oil in the pipeline.
    “we design the control systems to ELIMINATE/minimize flaring.”

    – “the pic on the page doesn’t seem normal : looks like they’re flaring ….bunker oil!”

  7. quick observation on your figs : 250 WORLD total flaring, 750 UK CO2,
    but the UK is only 1% of the world’s population ..so I expect World flaring to be quite a small proportion of world CO2

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