CNN: The 1.5-degree climate goal may be 'deader than a doornail,' and scientists are bitterly divided over it

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https://www.cnn.com/2024/01/18/climate/paris-climate-goal-threatened-intl/index.html

The 1.5-degree climate goal may be ‘deader than a doornail,’ and scientists are bitterly divided over it

By Laura Paddison, CNN
Updated 7:47 AM EST, Thu January 18, 2024

(CNN) — For years, the fight against climate change has been symbolized by one number: 1.5.

Ever since countries agreed in 2015 to an ambition of restricting global warming to 1.5 degrees Celsius above pre-industrial levels, the number has become synonymous with staving off catastrophic climate change.

But what if the battle to keep global warming from overshooting this limit has already been lost?

Some prominent scientists argue it has and it’s irresponsible to sugarcoat the truth. For others, that view is not only wrong, but even “dangerous.”

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1. CNN: The planet is heating up faster than predicted, says scientist who sounded climate alarm in the 1980s

https://www.cnn.com/2023/11/02/climate/the-planet-is-heating-up-faster-than-predicted-says-scientist-who-first-warned-the-world-about-climate-change/index.html

The planet is heating up faster than predicted, says scientist who sounded climate alarm in the 1980s

By Laura Paddison, CNN
Updated 1:19 PM EDT, Thu November 2, 2023

(CNN) — The planet is on track to heat up at a much faster rate than scientists have previously predicted, meaning a key global warming threshold could be breached this decade, according to a new study co-authored by James Hansen — the US scientist widely credited with being the first to publicly sound the alarm on the climate crisis in the 1980s.

In the paper, published Thursday in the journal Oxford Open Climate Change, Hansen and more than a dozen other scientists used a combination of paleoclimate data, including data from polar ice cores and tree rings, climate models and observational data, to conclude that the Earth is much more sensitive to climate change than previously understood.

“We are in the early phase of a climate emergency,” according to the report, which warns a surge of heat “already in the pipeline” will rapidly push global temperatures beyond what has been predicted, resulting in warming that exceeds 1.5 degrees Celsius above pre-industrial levels in the 2020s, and above 2 degrees Celsius before 2050.

The findings add to a slew of recent research that concludes the world is hurtling toward 1.5 degrees, a threshold beyond which the impacts of climate change — including extreme heat, drought and floods — will become significantly harder for humans to adapt to.

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[cachukis]

2. We are in predicament. Simply, plan well.

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3. I question how well anyone can plan at this point

Please note date of publication:

https://openatmosphericsciencejournal.com/contents/volumes/V2/TOASCJ-2-217/TOASCJ-2-217.pdf

The Open Atmospheric Science Journal, 2008, 2, 217-231

Target Atmospheric CO₂ : Where Should Humanity Aim?

James Hansen*,¹ ² , Makiko Sato¹ ² , Pushker Kharecha¹ ² , David Beerling³ , Robert Berner⁴ , Valerie Masson-Delmotte⁵ , Mark Pagani⁴ , Maureen Raymo⁶ , Dana L. Royer⁷ and James C. Zachos⁸

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Abstract: Paleoclimate data show that climate sensitivity is ~3°C for doubled CO₂, including only fast feedback processes. Equilibrium sensitivity, including slower surface albedo feedbacks, is ~6°C for doubled CO₂ for the range of climate states between glacial conditions and ice-free Antarctica. Decreasing CO₂ was the main cause of a cooling trend that began 50 million years ago, the planet being nearly ice-free until CO₂ fell to 450 ± 100 ppm ; barring prompt policy changes, that critical level will be passed, in the opposite direction, within decades. If humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted, paleoclimate evidence and ongoing climate change suggest that CO₂ will need to be reduced from its current 385 ppm to at most 350 ppm, but likely less than that. The largest uncertainty in the target arises from possible changes of non-CO₂ forcings. An initial 350 ppm CO₂ target may be achievable by phasing out coal use except where CO₂ is captured and adopting agricultural and forestry practices that sequester carbon. If the present overshoot of this target CO₂ is not brief, there is a possibility of seeding irreversible catastrophic effects.

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5. SUMMARY

Humanity today, collectively, must face the uncomfortable fact that industrial civilization itself has become the principal driver of global climate. If we stay our present course, using fossil fuels to feed a growing appetite for energy-intensive life styles, we will soon leave the climate of the Holocene, the world of prior human history. The eventual response to doubling pre -industrial atmospheric CO₂ likely would be a nearly ice-free planet, preceded by a period of chaotic change with continually changing shorelines.

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Present policies, with continued construction of coal-fired power plants without CO₂ capture, suggest that decision-makers do not appreciate the gravity of the situation. We must begin to move now toward the era beyond fossil fuels. Continued growth of greenhouse gas emissions, for just another decade, practically eliminates the possibility of near-term return of atmospheric composition beneath the tipping level for catastrophic effects.

The most difficult task, phase-out over the next 20-25 years of coal use that does not capture CO₂, is Herculean, yet feasible when compared with the efforts that went into World War II. The stakes, for all life on the planet, surpass those of any previous crisis. The greatest danger is continued ignorance and denial, which could make tragic consequences unavoidable.

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4. Annual CO₂ emissions

https://ourworldindata.org/explorers/co2?facet=none&hideControls=false&Gas+or+Warming=CO%E2%82%82&Accounting=Territorial&Fuel+or+Land+Use+Change=All+fossil+emissions&Count=Per+country&country=CHN~USA~IND~GBR~OWID_WRL

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5. Climate Reanalyzer: Daily Surface Air Temperature, World (90S-90N, 0-360E)

https://climatereanalyzer.org/clim/t2_daily/?dm_id=world

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6. Antarctic Sea Ice Extent (Area of ocean with at least 15% sea ice)

https://nsidc.org/arcticseaicenews/antarctic-daily-image-update/

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7. Global temperature relative to 1880-1920 based on the GISS analysis.

Global temperature relative to 1880-1920 based on the GISS analysis.¹ ² Projected El Nino warming and La Nina cooling discusses in text and decadal acceleration in Pipeline.³


Fig. 6. From Global Warming Acceleration: Causes and Consequences, James Hansen, et al.