Current volcanic activity and climate?

So what of the current eruptions? Well Bezymianny appears to be explosive enough, but its latitude (55 N) will tend to preclude it having any big climate impact. Merapi is in the right location but doesn’t appear (so far) to be explosive enough to put anything in the stratosphere, and so this too seems unlikely to impact climate. At some point, there will be another climatically important eruption, but it hasn’t happened yet…

Page 2 of 2 | Previous page

56 comments on this post.
  1. Grant:

    Re: #50

    Indeed, fig. 4 in Hansen et al. is solar forcing, not temperature. Also, the figure indicates solar irradiation in Watts per square meter. That’s the increase in solar energy intercepted by a square meter which is exposed to sunlight head-on. But earth’s surface area (4 pi r^2) is four times earth’s cross-sectional area (pi r^2), so any indicated change in solar irradiance should be divided by 4 to compute the change in solar forcing on earth.

    I’ve specifically looked for any hint of the 11-year solar cycle in the global temperature record, and found none. I’m not aware of any scientific work which claims there is a hint of it.

    Take a good look at Hansen et al.’s figure 5(a), to get an idea of the strength of solar forcing compared to that of greenhouse gases.

  2. Hank Roberts:

    Jack, look at the left side of that Fig. 4 — the scale is numbered and units shown.

    The bottom of the chart is not zero — the lowest number shown is 1364 watts per square meter.
    The highest number shown is 1367 watts per square meter. The curve doesn’t reach either of those.

    The difference between higher and lower parts of that curve is, eyeballing it, roughly 2 w/m-squared.

    That’s how much the sun is changing over that span of years. (That’s not how much reaches the ground or we’d all be toast!)

    The variation is small, very small. It’s real (Fig. 4 shows two estimates of what the sun actually did) — that difference does show up in Figure 6, as a very slight contribution to temperature change.

  3. Jack Lee:

    Can some one put things in perspective for me? How does our fossil fuel usage today compare to the Krakatoa erruption of 1883? Here is an excert of what that one event did to affect global temperature from wikipedia quote:
    The eruption produced erratic weather and spectacular sunsets throughout the world for many months afterwards, as a result of sunlight reflected from suspended dust particles ejected by the volcano high into Earth’s atmosphere. The area around Java is now known as Lady Bull because of its fiery nature. This worldwide volcanic dust veil acted as a solar radiation filter, reducing the amount of sunlight reaching the surface of the earth. In the year following the eruption, global temperatures were lowered by as much as 1.2 degrees Celsius on average. Weather patterns continued to be chaotic for years, and temperatures did not return to normal until 1888. British artist William Ashcroft made thousands of color sketches of the red sunsets half-way around the world from Krakatoa in the years after the eruption. In 2004, researchers proposed the idea that the blood-red sky shown in Edvard Munch’s famous 1893 painting The Scream is also an accurate depiction of the sky over Norway after the eruption.
    end quote.

  4. Hank Roberts:

    Jack, Google “+krakatoa +warming”

    See Hansen’s 1999 Congressional testimony — Scenario B.

  5. TT's Samurai Stumblings:

    Rudimentary climate science; the role of CO2, oceans and volcanoes…

    I am posting here a brief summary that I just sent to a Mises Blog contributor, in response to an inquiry…

  6. How many global warming equivalents does a volcano spew out? - PriusChat Forums:

    […] impact. Let me see if I can get a graph with Pinatubo labeled. Here’s a brief general discussion: RealClimate Can’t seem to find a graph handy, sorry. Several sources say the aerosols from Pinatubo were […]