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Climate Scientists Struggle for Consensus


The UN’s Intergovernmental Panel on Climate Change (IPCC) is preparing its latest Assessment Report (AR5) on the state of climate science, and is having to iron out disagreements between its scientist members. The vast majority of scientists agree that the Earth is warming, and that humans are culpable to some degree do to greenhouse gas emissions. But that’s where the consensus ends—climate models failed to predict a slowdown in warming in recent years, and climate scientists can’t agree on why. And, as the NYT reports, they’re struggling to agree on specific predictions for sea level and temperature rise in the latest IPCC report:

In one case, we have a lot of mainstream science that says if human society keeps burning fossil fuels with abandon, considerable land ice could melt and the ocean could rise as much as three feet by the year 2100. We have some outlier science that says the problem could be quite a bit worse than that, with a maximum rise exceeding five feet.

The drafters of the report went with the lower numbers, choosing to treat the outlier science as not very credible.

In the second case, we have mainstream science that says if the amount of carbon dioxide in the atmosphere doubles, which is well on its way to happening, the long-term rise in the temperature of the earth will be at least 3.6 degrees Fahrenheit, but more likely above 5 degrees. We have outlier science that says the rise could come in well below 3 degrees.

In this case, the drafters of the report lowered the bottom end in a range of temperatures for how much the earth could warm, treating the outlier science as credible.

You can almost see the Grey Lady shaking her head at panel’s inconsistency here: on sea level rise, they went with the more conservative mainstream numbers, but on temperature rise, they went with the more conservative fringe predictions. But there is a common thread in both decisions: given the flack the panel’s last report got for overstating its case and the recent warming plateau, it’s possible that the IPCC is making a conscious decision to err on the side of caution with AR5.

These quibbles are another reminder—as if we needed one—that our understanding of climate is still quite limited. Assigning specific numbers and narrow ranges to outcomes years down the road have already proved fiendishly difficult. It’s no surprise then that the IPCC is split on two key components of their upcoming report. These reports have always been at least as political as they are scientific.

[Earth image courtesy of NASA ESA]

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  • rheddles

    Time for the IPCC to just fade away.

  • ColoComment

    “These reports have always been at least as political as they are scientific.”

    And, they rely on models based on data that may, or may not, or some may and some may not, be accurate historical measurements.

    Smoke and mirrors. Show the raw data, show your work, and maybe your conclusions will be treated as serious. Until then, it’s all smoke and mirrors & doesn’t warrant the attention it’s gotten, thanks to the political and activist spongers.

  • Jacksonian_Libertarian

    “These reports have always been at least as political as they are scientific.”

    There is no place for politics in scientific endevors. The Truth is the Truth, and the rigorous use of the scientific method reveals the Truth. Politics can only negatively affect mankind’s effort at seeking the Truth.

  • Columbo1

    The reason that there is no consensus is because there has been no warming in the last 16 years rendering everyone of the myriad of IPCC climate models bereft of any predictive value. Meanwhile, media reports on the topic have returned to the level they were in 2004 and Al Gore has lost 90% of his staff and about 75% of his funding. The data is screaming that this more about just man-made CO2

    • Corlyss

      Maybe it is the hour before dawn in America.

  • Corlyss

    Okay. Now I think I’ve entered a parallel universe with this report from the NYT:

    “SACRAMENTO — A landmark law that has been a symbol of California’s tough environmental philosophy for more than 40 years is facing an unlikely challenge from Democrats, including Gov. Jerry Brown, who contend that regulations protecting the environment have been abused and are thwarting legitimate development.”

    Gov. Moonbeam speaks of rewriting the law as “the Lord’s Work.” To quote Chris Stevens, things like this “make me doubt my conception of reality.”

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