Friday, August 13, 2021

Forget the "hockey stick". Now we have the "scythe"

 From an article by Michael E Mann in Time Magazine.

“Widespread and severe”—that’s how climate scientists from around the world have described the impacts of climate change in a new United Nations report published today. The report’s findings further affirm warnings scientists like me have been sharing for decades. More than three decades ago, during a congressional hearing on a hot July 1988 afternoon in Washington, D.C., Dr. James E. Hansen told our elected officials that it was already possible to detect a warming of the planet due primarily to an increase in carbon dioxide concentrations from fossil fuel burning.

Hansen was prescient. It would take the United Nations’ Intergovernmental Panel on Climate Change (IPCC) another seven years after that to conclude that there was a “discernible human influence” on our climate. The IPCC, like many scientific institutions, is intrinsically conservative. So, when they state that the impacts of climate change are now “widespread and severe,”  it means that the impacts of climate change are now widespread and severe. Of course, you don’t need a scientific report to tell you that at this point. You need simply watch the unprecedented extreme weather disasters we’ve witnessed this summer play out in real time on our television screens and in our newspaper headlines.

With the release of the new Sixth Assessment report (“AR6”) on the science underlying the climate crisis, the news is not good. In addition to the finding that climate impacts are widespread and severe, the report shows that many severe impacts are locked in for the future.

Two decades ago, the so-called “hockey stick” curve, published by my co-authors and me in 1999, was featured in the all-important “summary for policy makers” (or “SPM”) of the 2001 Third IPCC Assessment report. The curve, which depicts temperature variations over the past 1,000 years based on “proxy” records such as tree rings, corals, and ice cores, showed the upward spiking of modern temperatures (the “blade”) as it dramatically ascends, during the industrial era, upward from the “handle” that describes the modest, slightly downward steady trend that preceded it.

Featured in the AR6 SPM now is an even longer hockey stick with an even sharper blade. [The "scythe"]

The new report also suggests that the recent warming is not only unprecedented over the past two millennia, but possibly, the past hundred millennia—let that sink in. As the IPCC report lays bare, we are engaged in a truly unprecedented and fundamentally dangerous experiment with the one planet we know that can support us and all other known life.

More than in its previous reports, the IPCC now truly connects the dots between fossil fuel burning, the warming of the planet, and the deadly extreme weather events we’re now enduring. And if we fail to act on the climate crisis, as the new report shows, we can expect more expansive wildfires, more intense hurricanes, hotter heat waves, and increasingly drenching flash floods. Given the horrific extreme weather we are already living through, you can trust me—we do not want this to get worse.

This is the cost we all are already paying for the delay that polluters have been sowing. It didn’t have to be this way. The fossil fuel industry knew a half century ago that their products—coal, oil, gas—would lead to the climate change future that we’re living in today. For them, the quick money was more important than being responsible corporate citizens to help build a sustainable future for mankind.

Instead, they spent millions of dollars on a massive disinformation campaign to convince the public and policymakers that climate change either wasn’t real, wasn’t a threat, or would be too expensive to do anything about (when in fact the opposite is very clearly true). They wrote a check that our children, grandchildren, and great-grandchildren will be forced to cash if we fail to act, and which will leave them with a climate that will become increasingly untenable for civilization as we know it. Thankfully, there’s still time to prevent that stark future from occurring.

The new IPCC report shows that we can prevent many of the worst impacts of climate change and keep warming below 1.5°C above preindustrial levels—the target of the global Paris Agreement. While some impacts—like more flooding in coastal areas, continued glacial melt and sea level rise—are now baked in, we can still take steps to ensure they don’t get much more severe. If we can reduce carbon emissions dramatically, and keep warming below 1.5°C, we could, for example, hold sea level rise to just a couple feet over the next century. If we fail, the report shows we could ultimately be facing 20 feet or more of global sea level rise, a scenario where we’d be forced to say farewell to the major coastal cities of the world.

It’s possible to turn the ship around, but it won’t be easy. The IPCC has determined that planetary warming of 1.5°C (and possibly even 2°C) will be exceeded in a matter of decades “unless deep reductions in carbon dioxide, methane, and other greenhouse gas emissions occur in the coming decades.” That means we must reduce our carbon pollution from transportation, electricity and other sectors here in the U.S., and around the world. Climate change will be costly and disruptive, but it’s not yet beyond our capacity to adapt.

To limit warming to 1.5 degrees,

  • Developed countries need to slash emissions by 50% by 2030, which means emissions need to fall by a compound 7.5% per annum.  This is feasible if we replace fossil fuels in electricity generation and transition our vehicle fleet to EVs and PHEVs.
  • Developing countries (especially China)  need to build no new coal power stations and must start step-by-step replacement of their aging coal-fired power stations, as well as shift their car/lorry fleets to EVs
  • To accelerate this process, fossil fuel subsidies must be withdrawn, and a carbon tax must be introduced.
It's not that hard, whatever the fossil fuel apologists say.

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