Arctic amplification has already peaked

Davy, Richard; Griewank, Philipp

doi:10.1088/1748-9326/ace273

Cited by 12 publications

(7 citation statements)

References 33 publications

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“…Using the mean global temperature projected by the CMIP6 ensemble mean (solid black curve in Figure 3d), the AA up to 2050 is limited to values between 2 and 3. A similar result was recently reported by Davy and Griewank (2023).…”

Section: Future Aa Projectionsupporting

confidence: 92%

High Values of the Arctic Amplification in the Early Decades of the 21st Century: Causes of Discrepancy by CMIP6 Models Between Observation and Simulation

Chylek,

Folland,

Klett

et al. 2023

JGR Atmospheres

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Arctic Amplification (AA) in the first decade of the 21st century has reached values between 4 and 5, with a subsequent decrease to current values of about 3.6, while the value was from 2 to 3 during the twentieth century. The ensemble mean of the CMIP6 models has difficulty in reproducing the recently observed high values of the AA. In this report, we identify the main reason for this difficulty to be the CMIP6 models overestimate of the mean global temperature trend since about 1990. The largest values of the AA are observed in winter and spring. A sharp AA peak in 1987 spring was caused by a peak in the Arctic temperature trend occurring at the same time as a dip in the trend of mean global temperature. The winter AA has increased almost monotonically since 1990. Dividing the AA between the Arctic land and ocean areas shows that the ocean area makes a larger contribution to the AA. Our future projection of the AA suggests an increasing AA for about the next decade, followed by a slow decrease to about 3.5 in the 2050s.

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Section: Future Aa Projectionsupporting

confidence: 92%

High Values of the Arctic Amplification in the Early Decades of the 21st Century: Causes of Discrepancy by CMIP6 Models Between Observation and Simulation

Chylek,

Folland,

Klett

et al. 2023

JGR Atmospheres

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“…Speci cally, Dai et al (2019) showed that AA weakens in model experiments with 1%/year CO 2 increases and xed SIC for surface ux calculations, and that negligible additional AA will occur after sea-ice completely melts away. Davy and Griewank (2023) con rmed this nding by showing that as the rate of sea-ice loss decreases in the future, concurrent AA weakens.…”

Section: Introductionmentioning

confidence: 63%

Arctic Climate Feedback Response to Local Sea-Ice Concentration and Remote Sea Surface Temperature Changes in PAMIP Simulations

Jenkins,

Dai,

Deser

2024

Preprint

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Local and remote processes have been suggested to drive Arctic amplification (AA) – the enhanced warming of the Arctic region relative to other areas under increased greenhouse gases. We use Polar Amplification Model Intercomparison Project (PAMIP) simulations with changes in Arctic sea-ice with fixed global sea surface temperature (SST), or changes in global SST with fixed Arctic sea-ice to untangle the climate response to Arctic sea-ice loss or SST-induced warming, respectively. In response to Arctic sea-ice loss, the surface albedo feedback activates in summer mainly to increase oceanic heat uptake, leading to weak summertime warming. During winter, Arctic sea-ice loss greatly enhances oceanic heat release, which produces Arctic bottom-heavy warming and triggers positive lapse rate and cloud feedbacks, leading to large AA. In contrast, enhanced atmospheric energy convergence into the Arctic becomes the dominant contributor to relatively small AA under global SST-induced warming. Water vapor feedback contributes to Arctic warming but opposes AA due to larger tropical than Arctic moistening under SST-induced warming with fixed Arctic sea-ice. We also find top-heavy to uniform (bottom-heavy) Arctic warming and moistening in the Arctic mid-upper (lower) troposphere in the SST (Arctic sea-ice) perturbation runs, producing a negative-neutral (positive) Arctic lapse rate feedback, respectively. Lastly, we show that the responses to global SST or polar SIC perturbations are linearly separable. Our results suggest that large AA is caused primarily by sea-ice loss and resultant local changes in surface fluxes, while increased poleward energy transport can only produce weak AA under fixed sea ice.

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“…Lastly, our results from the highest emission scenario suggest that AA is expected to continue at a rate more than twice as global average, even under the likelihood of seasonally ice-free conditions by mid-century. However, AA is unlikely to be as strong as in the early 2000s, where a peak value has been identified contemporaneous with a peak in sea ice loss (Davy and Griewank 2023). Again, this concurrent occurrence of peaking AA and sea ice loss hints to the crucial role of ice melt for the evolution of AA, and further suggests that if sea ice melts away entirely, the sea-ice control on the evolution of AA diminishes.…”

Section: Discussionmentioning

confidence: 96%

Current-climate sea ice amount and seasonality as constraints for future Arctic amplification

Linke,

Feldl,

Quaas

2023

Environ. Res.: Climate

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The recent Arctic sea ice loss is a key driver of the amplified surface warming in the northern high latitudes, and simultaneously a major source of uncertainty in model projections of Arctic climate change. Previous work has shown that the spread in model predictions of future Arctic amplification (AA) can be traced back to the inter-model spread in simulated long-term sea ice loss. We demonstrate that the strength of future AA is further linked to the current climate’s, observable sea ice state across the multi-model ensemble of the 6th Coupled Model Intercomparison Project (CMIP6). The implication is that the sea-ice climatology sets the stage for long-term changes through the 21st century, which mediate the degree by which Arctic warming is amplified with respect to global warming. We determine that a lower base-climate sea ice extent and sea ice concentration (SIC) in CMIP6 models enable stronger ice melt in both future climate and during the seasonal cycle. In particular, models with lower Arctic-mean SIC project stronger future ice loss and a more intense seasonal cycle in ice melt and growth. Both processes systemically link to a larger future AA across climate models. These results are manifested by the role of climate feedbacks that have been widely identified as major drivers of AA. We show in particular that models with low base-climate SIC predict a systematically stronger warming contribution through both sea-ice albedo feedback and temperature feedbacks in the future, as compared to models with high SIC. From our derived linear regressions in conjunction with observations, we estimate a 21st-century AA over sea ice of 2.47–3.34 with respect to global warming. Lastly, from the tight relationship between base-climate SIC and the projected timing of an ice-free September, we predict a seasonally ice-free Arctic by mid-century under a high-emission scenario.

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Arctic amplification has already peaked

Cited by 12 publications

References 33 publications

High Values of the Arctic Amplification in the Early Decades of the 21st Century: Causes of Discrepancy by CMIP6 Models Between Observation and Simulation

High Values of the Arctic Amplification in the Early Decades of the 21st Century: Causes of Discrepancy by CMIP6 Models Between Observation and Simulation

Arctic Climate Feedback Response to Local Sea-Ice Concentration and Remote Sea Surface Temperature Changes in PAMIP Simulations

Current-climate sea ice amount and seasonality as constraints for future Arctic amplification

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