Here There be Dragons: The One Degree Threshold

November 9, 2015

monstersBig milestone about to be crossed. Uncharted territory.

BBC:

Global temperatures are set to rise more than one degree above pre-industrial levels according to the UK’s Met Office.

Figures from January to September this year are already 1.02C above the average between 1850 and 1900.

If temperatures remain as predicted, 2015 will be the first year to breach this key threshold.

The world would then be half way towards 2C, the gateway to dangerous warming.

The new data is certain to add urgency to political negotiations in Paris later this month aimed at securing a new global climate treaty.

For researchers, confusion about the true level of temperatures in the 1750s, when the industrial revolution began and fossil fuels became widely used, means that an accurate assessment of the amount the world has warmed since then is very difficult.

Here James Hansen discusses the mythical 2 degree threshold.  In reality, with just a one degree warming,  civillization is already headed for very expensive and challenging upheavals.

BBC again:

Scientists say that the one degree mark will be broken in 2015 because of a combination of carbon emissions and the impact of the El Nino weather phenomenon.

“We have seen a strong El Nino develop in the Tropical Pacific this year and that will have had some impact on this year’s global temperature,” said Stephen Belcher, director of the Met Office Hadley Centre.

“We’ve had similar natural events in the past, yet this is the first time we’re set to reach the 1C marker and it’s clear that it is human influence driving our modern climate into uncharted territory.”

And Then There’s Physics:

Well, it depends on how you consider this. It’s taken us about 160 years to warm by about 1oC. This is associated with emissions of about 550GtC (550 billion tonnes of carbon, or ~2000 billion tonnes of CO2). Current emissions are around 10GtC/year. If we continue emitting as we are, we will double our cumulative emissions in about 50 years. If we continue to increase our emissions, it will be even sooner (H/T Aaron on Twitter). If we want to have a >66% chance of staying below 2oC, then we have a carbon budget of only about 250GtC (850GtCO2) from 2015, which we could reach in only 25 years at current emissions.

So, we might be halfway to 2oC in terms of temperature, but we’re much more than halfway there in terms of time. Of course, whether or not we should actually have a 2oC target, and an associated carbon budget, is a complex issue, but that doesn’t change that if we carry on as we are, the second 1oC will probably happen much faster the first.

5 Responses to “Here There be Dragons: The One Degree Threshold”


  1. I don’t think we want to know the consequences of 2C, methane outgassing is increasing off the Oregon Coast, NZ, the Arctic/ESS, Siberia and many more places to be discovered and the ocean has about a 40-50year lag on CO2 levels (a helluva a lot of mass in them thar waters). Plus the Geological/tectonic implications with even more rapid ice loss and gain in East Antarctica affecting rotational balance and axis.

    The oil industry as a whole was warned in 1959 and the US Government was officially warned in 1965.
    The wasted years, those who were responsible for the wasted years should be the ones paying for the expensive mitigation and repairs and recompense and getting that CO2 and other GHG’s down to 260ppm again, don’t know what they can do about the oceans though

    • dumboldguy Says:

      Well said. Yes, “don’t know what they can do about the oceans though” is one of my big concerns also. My prediction? Once the SHTF big time, get ready for some massive and panicky geoengineering proposals. Seeding the oceans with iron, and with salt (to restore thermohaline circulation), turning the skys yellow with sulfur, etc.

  2. gdo22 Says:

    The issue is, if Bill McKibben’s Rolling Stone “Global Warming’s Terrifying Math” article is to be believed, then once we pass the 1 degree Celsius mark, we’ve locked in the 2 degree Celsius mark as well, unless we can come up with some technology to suck the CO2 out of the atmosphere. CO2 that’s emitted into the atmosphere tends to stay there, and continues to work its magic for many years. When McKibben wrote his article, he stated that the 0.8 degrees Celsius of the time really meant that 1.6 degrees Celsius were locked in, (barring some technology that can suck out the CO2, of course).

    I think it was on Vox that I read that one economist had said in his book (called Climate Casino) that 2.5 degrees Celsius above preindustrial temperatures was where the pros and cons met. Of course I’m not saying that we should shift our target now. I’m just saying that we need to go hard on this issue, so that even that risky proposal doesn’t become reality.

  3. Kc Herring Says:

    Out of all my somewhat well informed.friends More than 92% are oblivious too or even downright deniaists of the dangers of even 1 degree They somehow feel that because they are well off financially they are intitled to do whatever they want. One is getting ready to build a vacation home in Costa Rica. OMG
    Some of the “more” well informed ppl. On here are starting to understand that 1 degree is much much much worst than we realized even 1 or 2 years ago
    The only way the 92% are going to change there ways is when they are dead. They might pretend to be helping by installing solar panels But then they book a cruise or buy a motor home or worse. It’s human nature of addiction and the feeling of entitlement that is more or less built into our very genes
    1 degree or 2 degrees does not sound scary enough to most ppl. Even the complete shut down of the shellfish industry on the east coast and the natural salmon GONE on the west are not going to slow the 92% on their ever increasing personal carbon footprint. If anything it gets worse with the lush government pensions They really don’t have much else to do with all that money.
    There really is no ” fix” beyond a very slow (and painful) transformation. Uh Ohh

    • dumboldguy Says:

      I’ll repeat myself and say that it will take major SHTF on a daily and planet-wide basis before people pay much attention, and even then they won’t unless it hits them personally (and most will then just say it was “bad luck”).

      I’ve touted Gilding’s The Great Disruption before—-Gilding gives a good description of what is coming when the SHTF—-worth reading.

      You and I are part of it as well. We may be more aware of the facts of AGW, but we too live a “Western developed country lifestyle” and are not about to give it up. We may feel guilty about that and take small steps to mitigate our carbon footprint and fight AGW, but we are NOT going to ditch it all and go back to a hunter-gatherer subsistence lifestyle. The deniers challenge us by saying “stop using fossil fuels if you’re worried about AGW”, but that’s a juvenile argument.

      And as for the “transformation”, the third world wants to live like us and is burning ever more fossil fuel (Time out to shout INDIA-COAL-INDONESIA). Don’t hold your breath.


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