Mastodawn

the world has failed to meet its main #ClimateChange target of limiting the rise in global temperatures to 1.5°C, & will likely breach this threshold in the next decade, the #UN' #Environment Program said Tuesday.

The annual #EmissionsGap report said because of countries' slow action to reduce planet-heating #GreenhouseGas #emissions, it was now clear that the world would exceed the core target of the 2015 #ParisAgreement - at least temporarily.

#ClimateCrisis
https://www.reuters.com/sustainability/cop/world-will-overshoot-15c-climate-goal-un-says-2025-11-04/

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Nonilex Nov 4

"This will be difficult to reverse—requiring faster & bigger additional reductions in #GreenhouseGas #emissions to minimize overshoot," #UNEP said.

Lead report author Anne Olhoff said deep emissions cuts now could delay when the overshoot happens, "but we can no longer totally avoid it".

The 2015 #ParisAgreement commits countries to limit the global average temperature rise to 2°C above pre-industrial levels, & to aim for 1.5°C.

#ClimateChange #ClimateCrisis

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Nonilex Nov 4

Yet govts' latest pledges to cut #emissions in future, if met, would see the world face 2.3-2.5°C of warming, #UNEP said.

That's around 0.3°C less warming than the UN's projection a year ago—indicating that new emissions-cutting plans announced this year by countries including top #CO2 emitter #China have failed to substantially close the gap.

China pledged in Sept to cut emissions by 7-10% from their peak by 2035. Analysts note China tends to set modest targets & exceed them.

#ClimateChange

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Nonilex Nov 4

The findings add pressure to the UN's #COP30 #climate summit this month, where countries will debate how to rein in #GlobalWarming.

The #ParisAgreement temperature goals were based on scientific assessments of how each increment of warming fuels worse #heatwaves, #droughts & #wildfires. For example, 2°C of warming would more than double the share of the population exposed to #ExtremeHeat, compared with 1.5°C . Warming of 1.5°C would destroy at least 70% of #CoralReefs, versus 99% at 2°C.

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Nonilex Nov 4

Current policies - the ones countries already have in place - would lead to even more warming, of around 2.8°C, #UNEP said.

The world has made some progress. A decade ago, when the #ParisAgreement was signed, the planet was on course for around a 4°C temperature rise.

But heat-trapping #CO2 #emissions continue to rise, as countries burn #coal, #oil & #gas to power their economies.

Global #GreenhouseGas #emissions increased by 2.3% in 2024, to 57.7 gigatonnes of CO2 equivalent, UNEP said.

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Richard Michael Blaber Nov 4

@Nonilex This is an under-estimate, I'm afraid. The current level of #CO2 is the same as that of the Mid-Piacenzian Warm Period of the Pliocene Epoch (https://www.nature.com/articles/s41598-020-67154-8), when #globalwarming was at 3C. It is only the cooling aerosols in our #atmosphere that are keeping temperatures at half that level. Measures to eliminate #airpollution will remove these aerosols, without getting rid of the GHGs.

Atmospheric CO2 during the Mid-Piacenzian Warm Period and the M2 glaciation - Scientific Reports

The Piacenzian stage of the Pliocene (2.6 to 3.6 Ma) is the most recent past interval of sustained global warmth with mean global temperatures markedly higher (by ~2–3 °C) than today. Quantifying CO2 levels during the mid-Piacenzian Warm Period (mPWP) provides a means, therefore, to deepen our understanding of Earth System behaviour in a warm climate state. Here we present a new high-resolution record of atmospheric CO2 using the δ11B-pH proxy from 3.35 to 3.15 million years ago (Ma) at a temporal resolution of 1 sample per 3–6 thousand years (kyrs). Our study interval covers both the coolest marine isotope stage of the mPWP, M2 (~3.3 Ma) and the transition into its warmest phase including interglacial KM5c (centered on ~3.205 Ma) which has a similar orbital configuration to present. We find that CO2 ranged from $${{\bf{394}}}_{{\boldsymbol{-}}{\bf{9}}}^{{\boldsymbol{+}}{\bf{34}}}$$ ppm to $${{\bf{330}}}_{{\boldsymbol{-}}{\bf{21}}}^{{\boldsymbol{+}}{\bf{14}}}$$ ppm: with CO2 during the KM5c interglacial being $${{\bf{391}}}_{{\boldsymbol{-}}{\bf{28}}}^{{\boldsymbol{+}}{\bf{30}}}$$ ppm (at 95% confidence). Our findings corroborate the idea that changes in atmospheric CO2 levels played a distinct role in climate variability during the mPWP. They also facilitate ongoing data-model comparisons and suggest that, at present rates of human emissions, there will be more CO2 in Earth’s atmosphere by 2025 than at any time in at least the last 3.3 million years.

Nature

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