How Many Hiroshima Bombs per Second?

Okay, it happened again. Just this week, an article on mainstream media used the Hiroshima Bombs per Second (HpS) metaphor to describe how fast the planet is heating up. This time the conclusion was that the oceans are heating up at a rate of 5 HpS. And they got it Wrong! Wrong! Very wrong!

The calculation of HpS is straightforward and depends on a number called the Earth Energy Imbalance or EEI. This number is the difference between the totality of incoming solar radiation and outgoing radiation of all forms. The EEI is expressed in the units of Watts per square meter (W/m²). As Dr. James Hansen said on Twitter last December, “Earth’s energy imbalance is the best diagnostic of where climate is heading.”

In this article I computed HpS based on the EEI as published by NASA for the annualized 12 month period March 2021 to February 2022. My answer was 13.3 HpS globally. Given that about 90% of the EEI is captured by the oceans, this means about 12 HpS warming the oceans.

I’ve been eagerly awaiting an update to the NASA data. Just this week, thanks to some help by Leon Simmons, I was able to go to the CERES website and download the EEI data through August, 2022.

It turns out that the February 2022 number was a local maximum and things have been declining a bit since then. For the 12-month period September 2021 to August 2022, the EEI was 1.40 W/m², the equivalent of 11.4 HpS globally and 10.3 HpS into the oceans. Here is the full HpS record using a 12-month running mean:

But this isn’t the end of the story. In this Tweet, Dr. Hansen presented a graph of the EEI that included the most recent data through August, 2022 (now updated through November, 2022). In it, Dr. Hansen references the September 2019 to August 2022 36-month running mean, showing it as 1.22 W/m².

There’s a good reason to take the long view. As you can see by the graph above, there is a lot of year-to-year variability in the EEI. This variability is caused by many factors, including ENSO and other climate cycles, the solar cycle, global cloud cover, volcanism and any number of anthropogenic influences including the recent Covid slowdown. Taking the long view allows us to smooth out this noise and get a better perspective on the long-term trend for the EEI.

Here is the graph of the 36-month running mean of the EEI expressed in HpS, together with a linear trendline:

The August data point on this graph corresponds to Dr. Hansen’s 1.22 W/m², which is equivalent to 9.91 HpS globally or 8.9 HpS into the oceans. With reference to the CBSNews article, our sad planet passed the 5 HpS milestone a decade ago.

Looking deeper into this graph, it is just stunning to see that the EEI has risen from about 3 HpS back in 2003 to about 10 HpS today. The EEI has more than tripled in 20 years. That means triple the heat being captured by rising greenhouse gasses. Triple the heat melting the poles, heating the oceans, super-charging storms, baking our continents. Triple the rate of “warming” of our planet.

The next graphic tells how the EEI has changed over time by month, again using the CERES data.

What I did here was to get the average EEI for each of the 12 months of the year, with the average taken from 2000 to 2022.  I then looked at each month and computed the difference of the EEI for that month and the overall average EEI for the same month.  I then colored the month, using a shade of blue if the month was below average and a shade of red if it was above average. The darker the shade, the greater the deviation from average.

You can easily see from this graphic that the tendency is towards red in all months. In other words, the EEI is growing year round.  As the years pass, the planet is absorbing more and more heat. But some months are getting redder faster than others.

The following chart measures the change in HpS by month in a way that lets us determine which month is heating up fastest. Rather than measuring the overall average HpS for each month over the period 2000-2022, what I did was to compute two averages. The first was the average HpS for each month over the period 2000-2017 and the second was to compute the average HpS over the last 5 years, 2018-2022.  I then measured how much HpS had increased each month between those two averages.  This is what I got:

As you can see from this, the month of June is the clear leader. In fact, the number of HpS for June has increased by an average of 7.4 over the last 5 years, while December’s HpS has increased by only 1.4.  In simple terms, June is heating up faster than any other month.

There is no other metric that truly underscores how fast the changes are happening on our planet. Not the Keeling curve or other monthly measurements of greenhouse gasses. Not the rapidly shrinking global ice. Not the rapid rise of the global mean temperature over the 1850-1900 IPCC baseline. Not the burn scars across Siberia and the Amazon. Not the loss of species and habitats. None of these shows what the Earth energy imbalance shows.

The metric of HpS is one that we humans understand. We all have seen pictures of atomic explosions. Their heat is immense. The damage that even one explosion can do to a city is devastating. And yet, here we are, lighting off 9.91 of these bombs every second, nearly 36,000 an hour, over 850,000 a day. Humans have “warmed” the planet by the equivalent of 935,000,000 (935 million) Hiroshima nuclear bombs over the last three years.

We can go even further. If we look at the average HpS over the last 20 years (the period September 2002 – August 2022), then it turns out that the long-term average is about 6.74 HpS globally and about 6.1 HpS into the oceans. At the very lowest end, this is the minimum number mainstream media should report. Anything less than reporting the oceans heating at a rate of 6 HpS (like the CBSNews article) is just hogwash innumerate reporting. And this value is averaged over 20 years, not the most recent value at all.

Adding the last 20 years all up, we get total warming due to the EEI over the last 20 years equivalent to lighting off 4,250,000,000 (4.25 billion) Hiroshima nuclear bombs, of which about 3.8 billion went into heating the oceans.

Our planet is on fire and the fire is getting hotter. We, together with all the living breathing species on our planet, are hurtling towards our collective oblivion. Be kind. Be generous. Be of service.

Eliot Jacobson, Ph.D.

Retired professor of mathematics and computer science, retired casino consultant, now a full time volunteer, husband and grandfather. Know-it-all doomer. Born in the year 316 ppm CO2.

9 thoughts on “How Many Hiroshima Bombs per Second?

  • January 16, 2023 at 7:23 am

    Great piece!!! Stay safe!!

  • January 16, 2023 at 7:48 am

    And some are worried of a nuclear threat and winter, while been bombing ourselves all along!
    Thanks for the correction and perspectives, Elliot

  • January 16, 2023 at 9:21 am

    Thanks for this, but there is another metric to demonstrate the negative effects of the same population density stress that’s driving global warming and that’s our collapsing health: 55-60% of adult Americans have at least one serious chronic medical condition requiring ongoing medical attention, one in five (20%) of working adults (20-50yo) are dying from alcohol related diseases, our youth are ever more faced with the bleak future and suffering from the “diseases of despair” (Deatons), and all of this is accelerating parallel to the ocean warming (heating) graph. BTW, each and every human living today is producing 160 BTUs/hr from metabolism, so 160 X 24 X 365 X 8B. You do the math! And yet, we insist on following the advertising dictates of corporate America to travel in fossil fuel burning machines and the world burned 8B metric tons of coal last year, one for every man, woman, and child on the dying planet. Is this really the world we should be bringing another innocent life kicking and screaming into? Stress R Us

    • January 16, 2023 at 10:33 am

      I’d say the difference is that HpS is a global metric — your metric referencing Americans would be more telling if it could be expressed globally. We know a lot about global hunger, poverty, disease and addiction. For example:

      Everything is headed full speed in the wrong direction.

      Thank you for the good work you do as an MD.

  • January 16, 2023 at 5:20 pm

    When i saw the CBS article in a thread i was furious, knowing that you’ve already proven it’s way way beyond that. Mainstream just can’t be trusted, at all

  • January 17, 2023 at 12:29 am

    I accept the physics. We really are “lighting off 9.91 of these bombs every second, nearly 36,000 an hour, over 850,000 a day.”, but for lack of a recognizable equivalent I can’t get my head around how much energy that is on some familiar scale. And I suspect many reject the analogy to Hiroshima bombs per second out of hand because 800K of these explosions a day just seems incomprehensible. The heat is immense but how much heat, and what could that heat otherwise do in in the world? Would it translate into, say, total human energy consumption per day for X amount of time? Our total household electricity consumption per century?

    One Hiroshima bomb is said to release 63,000,000,000,000 (trillion) joules of energy, a joule being a unit of heat. Holy crap! What can one joule do? What I found on Wikipedia for “practical examples” isn’t helping:

    “The amount of electricity required to run a 1 W device for 1 s.
    The energy required to accelerate a 1 kg mass at 1 m/s2 through a distance of 1 m.
    The kinetic energy of a 2 kg mass travelling at 1 m/s, or a 1 kg mass travelling at 1.41 m/s.
    The energy required to lift a medium-sized tomato up 1 metre (3 ft 3 in), assuming the tomato has a mass of 101.97 grams (3.597 oz). (!!!!!!!)
    The heat required to raise the temperature of 0.239 g of water from 0 °C to 1 °C, or from 32 °F to 33.8 °F.”
    [link removed by EJ]

    So, if 1 joule lifts a medium-sized tomato up 1 metre, 63T joules will raise the tomato 63T metres or ~39B miles, roughly 14 times the distance from here to Neptune. No help there. More thought needed.

  • February 8, 2023 at 2:50 pm

    This is very interesting and many words beyond that. However I’m really puzzled by the discrepancy between 5 and 10+ HpS. I’m just going to take the math you have laid out and in other pieces as correct. So how did the authors arrive at 5? Were they using older data? Was the data normalized in someway not done in this article? Otherwise to assume the 24 people who put their names on are flat wrong or liars seems to far a stretch. Michael Mann signed off on this report.

    • February 8, 2023 at 3:47 pm

      I am as equally puzzled as you at how the numbers 3, 4, 5 and so on have lingered so long, even as the number has crept up, hitting 13.33 HpS in February, 2022 (based on the 12-month running mean). Before I published, I had my work checked by two individuals, one of whom was the person who originally came up with the HpS metric way back when. A famous meteorologist I follow on Twitter would not accept my work, but instead went with a source that was based on 2012 data. I have no idea …


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