New NASA model: Doubled CO2 means just 1.64°C warming

'Important to get these things right', says scientist


A group of top NASA boffins says that current climate models predicting global warming are far too gloomy, and have failed to properly account for an important cooling factor which will come into play as CO2 levels rise.

According to Lahouari Bounoua of NASA's Goddard Space Flight Center, and other scientists from NASA and the US National Oceanic and Atmospheric Administration (NOAA), existing models fail to accurately include the effects of rising CO2 levels on green plants. As green plants breathe in CO2 in the process of photosynthesis – they also release oxygen, the only reason that there is any in the air for us to breathe – more carbon dioxide has important effects on them.

In particular, green plants can be expected to grow as they find it easier to harvest carbon from the air around them using energy from the sun: thus introducing a negative feedback into the warming/carbon process. Most current climate models don't account for this at all, according to Bounoua. Some do, but they fail to accurately simulate the effects – they don't allow for the fact that plants in a high-CO2 atmosphere will "down-regulate" and so use water more efficiently.

Bounoua and her colleagues write:

Increase in precipitation contributes primarily to increase evapotranspiration rather than surface runoff, consistent with observations, and results in an additional cooling effect not fully accounted for in previous simulations with elevated CO2.

The NASA and NOAA boffins used their more accurate science to model a world where CO2 levels have doubled to 780 parts per million (ppm) compared to today's 390-odd. They say that world would actually warm up by just 1.64°C overall, and the vegetation-cooling effect would be stronger over land to boot – thus temperatures on land would would be a further 0.3°C cooler compared to the present sims.

International diplomatic efforts under UN auspices are currently devoted to keeping global warming limited to 2°C or less, which under current climate models calls for holding CO2 to 450 ppm – or less in many analyses – a target widely regarded as unachievable. Doubled carbon levels are normally viewed in the current state of enviro play as a scenario that would lead to catastrophe; that is, to warming well beyond 2°C.

It now appears, however, that the previous/current state of climate science may simply have been wrong and that there's really no need to get in an immediate flap. If Bounoua and her colleagues are right, and CO2 levels keep on rising the way they have been lately (about 2 ppm each year), we can go a couple of centuries without any dangerous warming. There are lots of other factors in play, of course, but nonetheless the new analysis is very reassuring.

"As we learn more about how these systems react, we can learn more about how the climate will change," says Bounoua's colleague Forrest Hall, in a NASA statement accompanying the team's scholarly paper. "Each year we get better and better. It's important to get these things right."

The NASA/NOAA boffins' paper Quantifying the negative feedback of vegetation to greenhouse warming: A modeling approach is published in the journal Geophysical Research Letters (subscription required). ®


Other stories you might like

  • Despite global uncertainty, $500m hit doesn't rattle Nvidia execs
    CEO acknowledges impact of war, pandemic but says fundamentals ‘are really good’

    Nvidia is expecting a $500 million hit to its global datacenter and consumer business in the second quarter due to COVID lockdowns in China and Russia's invasion of Ukraine. Despite those and other macroeconomic concerns, executives are still optimistic about future prospects.

    "The full impact and duration of the war in Ukraine and COVID lockdowns in China is difficult to predict. However, the impact of our technology and our market opportunities remain unchanged," said Jensen Huang, Nvidia's CEO and co-founder, during the company's first-quarter earnings call.

    Those two statements might sound a little contradictory, including to some investors, particularly following the stock selloff yesterday after concerns over Russia and China prompted Nvidia to issue lower-than-expected guidance for second-quarter revenue.

    Continue reading
  • Another AI supercomputer from HPE: Champollion lands in France
    That's the second in a week following similar system in Munich also aimed at researchers

    HPE is lifting the lid on a new AI supercomputer – the second this week – aimed at building and training larger machine learning models to underpin research.

    Based at HPE's Center of Excellence in Grenoble, France, the new supercomputer is to be named Champollion after the French scholar who made advances in deciphering Egyptian hieroglyphs in the 19th century. It was built in partnership with Nvidia using AMD-based Apollo computer nodes fitted with Nvidia's A100 GPUs.

    Champollion brings together HPC and purpose-built AI technologies to train machine learning models at scale and unlock results faster, HPE said. HPE already provides HPC and AI resources from its Grenoble facilities for customers, and the broader research community to access, and said it plans to provide access to Champollion for scientists and engineers globally to accelerate testing of their AI models and research.

    Continue reading
  • Workday nearly doubles losses as waves of deals pushed back
    Figures disappoint analysts as SaaSy HR and finance application vendor navigates economic uncertainty

    HR and finance application vendor Workday's CEO, Aneel Bhusri, confirmed deal wins expected for the three-month period ending April 30 were being pushed back until later in 2022.

    The SaaS company boss was speaking as Workday recorded an operating loss of $72.8 million in its first quarter [PDF] of fiscal '23, nearly double the $38.3 million loss recorded for the same period a year earlier. Workday also saw revenue increase to $1.43 billion in the period, up 22 percent year-on-year.

    However, the company increased its revenue guidance for the full financial year. It said revenues would be between $5.537 billion and $5.557 billion, an increase of 22 percent on earlier estimates.

    Continue reading

Biting the hand that feeds IT © 1998–2022