the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Impacts of reductions in anthropogenic aerosols and greenhouse gases toward carbon neutrality on dust pollution
Abstract. To mitigate future global warming, many countries have implemented rigorous climate policies for carbon neutrality. Given some shared emission sources with greenhouse gases (GHGs), aerosol particles and their precursor emissions are expected to be reduced as the consequences of global efforts in climate mitigation and environmental improvement, potentially inducing complex climate feedbacks. Here, we assess the large-scale impacts of reductions in anthropogenic GHGs and aerosol under a carbon neutral scenario in 2060 on dust emissions and concentrations over the low- to mid-latitudes in the Northern Hemisphere using the fully coupled Community Earth System Model. Our findings demonstrate a decline in atmospheric dust loading toward carbon neutrality (SSP1-1.9) relative to the high fossil fuel scenario (SSP5-8.5). Mechanistic analysis reveals counteracting modulation mechanisms: (i) Reductions in aerosols amplify surface downwelling shortwave radiation, convection and wind speed, thereby promoting dust emissions; (ii) GHGs reductions diminish the land-ocean thermal contrast and wind speed, suppressing dust emissions. The latter drives the future dust responses. These results highlight that carbon neutral strategies not only achieve climate mitigation goals and air quality improvements, but also generate synergistic benefits through dust pollution suppression.
Competing interests: At least one of the (co-)authors is a member of the editorial board of Atmospheric Chemistry and Physics.
Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.- Preprint
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Status: open (until 01 Sep 2025)
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RC1: 'Comment on egusphere-2025-2950', Mónica Zamora Zapata, 11 Aug 2025
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Please see the attached PDF.
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RC2: 'Comment on egusphere-2025-2950', Anonymous Referee #2, 22 Aug 2025
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This study investigates an interesting and underexplored aspect of climate policy: the unintended consequences of pursuing carbon neutrality on mineral dust pollution. Using the fully coupled Community Earth System Model (CESM1), the authors conduct a set of sensitivity experiments to investigate the individual and combined impacts of reducing greenhouse gases (GHGs) and aerosols under a carbon-neutral scenario versus a high-emission scenario on future dust emissions and concentrations. The authors conclude that GHG reductions and their associated dust-suppressing effect dominate the overall response, offsetting the dust increase caused by aerosols. This highlights important implications of decarbonisation beyond improvements in air quality and emphasises the complex and competing geophysical feedbacks.
The study is interesting and relevant. However, I feel the authors should address several comments before full acceptance.
Major comments:
Introduction: somewhat fragmented, I believe it would benefit from some re-organisation. Also, it would be good to highlight and organise by mechanisms/phenomena. The novelty of this study and the gaps need to be better and more clearly presented.
Changes in vegetation are not mentioned, yet I presume they are included and differ between the future scenarios, and they are expected to exert a significant influence on dust emissions.
Section 2.3: The comparison between the model’s multi-year climatology and 1 year observations is somewhat unfair and biased. The authors should use a multi-year observational record.
While the authors focus on March-May as this is the season when the largest dust emissions occur, I believe it is even more important to display and describe annual-mean changes, as some effects may partially compensate for the annual mean. Annual means are also more directly placed into the context of global warming, etc. Some other mechanisms are also at play in other seasons. I also wonder whether the prevalence of the GHG-related signal would occur in other seasons, for example JJA, when we expect a strong Asian monsoon response to regional aerosol changes.
The mechanistic analysis is overall sound but has also some points that need to be better and more clearly investigated. For example, some changes displayed in Fig 5 are not collocated with dust emissions (e.g., PBL changes). Aerosol emission changes are mostly over Asia, leading to large regional increases in surface radiation and temperature. How is the signal propagating to remote areas such as North Africa? How is surface wind changing in remote areas? Similarly, how can the authors explain the change in surface wind (not necessarily meridional only) by variations in the meridional temperature gradient under GHG forcing? More physical and dynamical insights are needed.
It would be interesting to expand the discussion on linearities (or lack of) in the combined GHG+AER response.
Finally, results should be more extensively discussed in the context of existing studies. Can the authors infer some qualitative conclusions on what would happen with other CMIP6 models (even if these specific experiments do not exist) with different climate sensitivities and aerosol radiative forcing? Do we expect GHG to dominate as well?
Minor comments:
The tile is not fully clear, particularly “toward carbon neutrality”.
Introduction: I would replace the word “demonstrated” with found, showed, etc.
L57: “Dust have been demonstrated”, rephrase
L76: Is the decreased warming continuing to present day? As the paragraph is discussing the effects of anthropogenic factors, this sentence is a bit disconnected from the broader context.
L81: Regarding the link between GHG and the NAO, is that also valid in the future?
L86: “global warming induced surface warming” redundant
L90: add some context concerning the period
L146-156: confusing
Section 2.2: a brief description of why ssp119 is carbon neutral and why the authors chose 2060 as the reference year.
L243: present the …
L245: they are not time-varying, they are fixed at 2060 values
L330: monsoon? The monsoon season in summer…
Citation: https://doi.org/10.5194/egusphere-2025-2950-RC2
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