The transient sensitivity of sea level rise

Climate Models ◽

Carbon Dioxide Emission ◽

Rate Of Change ◽

Intergovernmental Panel ◽

Transient Climate Response ◽

Abstract. Recent assessments from the Intergovernmental Panel on Climate Change implies that global mean sea level is unlikely to rise more than about 1.1 m within this century, but with further increase beyond 2100, even within the most intensive future anthropogenic carbon dioxide emission scenarios. However, some studies conclude that considerably greater sea level rise could be realized, and experts assign a substantially higher likelihood of such a future. To understand this discrepancy, it would be useful to have scenario independent metrics that can be compared between different approaches. The concept of a transient climate response has proven to be useful to compare the response of climate models. Here, we introduce a similar metric for sea level science. By analyzing mean rate of change in sea level (not sea level itself), we identify a near linear relationship with global mean surface temperature (and therefore accumulated carbon dioxide emissions) in both model projections, and in observations on a century time scale. This motivates us to define the Transient Sea Level Sensitivity as the increase in the sea level rate associated with a given warming in units of m/century/K. We find that model projections fall below extrapolation based on recent observational records. This comparison indicates that the likely upper level of sea level projections in recent IPCC reports would be too low.

The transient sensitivity of sea level rise

Ocean Science ◽

10.5194/os-17-181-2021 ◽

2021 ◽

Vol 17 (1) ◽

pp. 181-186

Author(s):

Aslak Grinsted ◽

Jens Hesselbjerg Christensen

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Radiative Forcing ◽

Climate Models ◽

Climate Model ◽

Greenhouse Gas Emission ◽

Rate Of Change ◽

Intergovernmental Panel ◽

Abstract. Recent assessments from the Intergovernmental Panel on Climate Change (IPCC) imply that global mean sea level is unlikely to rise more than about 1.1 m within this century but will increase further beyond 2100. Even within the most intensive future anthropogenic greenhouse gas emission scenarios, higher levels are assessed to be unlikely. However, some studies conclude that considerably greater sea level rise could be realized, and a number of experts assign a substantially higher likelihood of such a future. To understand this discrepancy, it would be useful to have scenario-independent metrics that can be compared between different approaches. The concept of a transient climate sensitivity has proven to be useful to compare the global mean temperature response of climate models to specific radiative forcing scenarios. Here, we introduce a similar metric for sea level response. By analyzing the mean rate of change in sea level (not sea level itself), we identify a nearly linear relationship with global mean surface temperature (and therefore accumulated carbon dioxide emissions) both in model projections and in observations on a century scale. This motivates us to define the “transient sea level sensitivity” as the increase in the sea level rate associated with a given warming in units of meters per century per kelvin. We find that future projections estimated on climate model responses fall below extrapolation based on recent observational records. This comparison suggests that the likely upper level of sea level projections in recent IPCC reports would be too low.

Global mean thermosteric sea level projections by 2100 in CMIP6 climate models

10.5194/egusphere-egu21-1934 ◽

2021 ◽

Author(s):

Svetlana Jevrejeva ◽

Hindumathi Palanisamy ◽

Luke Jackson

Keyword(s):

Thermal Expansion ◽

Sea Level Rise ◽

Sea Level ◽

Climate Models ◽

Coupled Model ◽

Rate Of Change ◽

Historical Period ◽

Coastal Zones ◽

Ensemble Mean ◽

Most of the excess energy stored in the climate system is taken up by the oceans leading to thermal expansion and sea level rise. Future sea level projections allow decision-makers to assess coastal risk, develop climate resilient communities and plan vital infrastructure in low- elevation coastal zones. Confidence in these projections depends on the ability of climate models to simulate the various components of future sea level rise. In this study we estimate the contribution from thermal expansion to sea level rise using the simulations of global mean thermosteric sea level from 15 available models in the Coupled Model Intercomparison Project Phase (CMIP) 6. We calculate a global mean thermosteric sea level rise of 18.8 cm [12.8 - 23.6 cm, 90% range] and 26.8 cm [18.6 - 34.6 cm, 90% range] for the period 2081&#8211;2100, relative to 1995-2014 for SSP245 and SSP585 scenarios respectively. In a comparison with a 20 model ensemble from CMIP5, the CMIP6 ensemble mean of future global mean thermosteric sea level rise (2014-2100) is higher for both scenarios and shows a larger variance. By contrast, for the period 1901-1990, global mean thermosteric sea level from CMIP6 has half the variance of that from CMIP5. Over the period 1940-2005, the rate of CMIP6 ensemble mean of global mean thermosteric sea level rise is 0.2 &#177; 0.1 mm yr-1, which is less than half of the observed rate (0.5 &#177; 0.02 mm yr-1). At a multi-decadal timescale, there is an offset of ~10 cm per century between observed/modelled thermosteric sea level over the historical period and modelled thermosteric sea level over this century for the same rate of change of global temperature. We further discuss the difference in global mean thermosteric sea level sensitivity to the changes in global surface temperature over the historical and future periods.&#160;

Gaussian Process emulation of multi-model ice sheet and glacier projections

10.5194/egusphere-egu21-14561 ◽

2021 ◽

Author(s):

Tamsin Edwards ◽

Keyword(s):

Gaussian Process ◽

Sea Level Rise ◽

Sea Level ◽

Climate Models ◽

Ice Sheet ◽

Surface Air Temperature ◽

Model Parameters ◽

Gaussian Process Emulation ◽

Model Ensembles ◽

The land ice contribution to global mean sea level rise has not yet been predicted with ice sheet and glacier models for the latest set of socio-economic scenarios (SSPs), nor with coordinated exploration of uncertainties arising from the various computer models involved. Two recent international projects (ISMIP6 and GlacierMIP) generated a large suite of projections using multiple models, but mostly used previous generation scenarios and climate models, and could not fully explore known uncertainties. Here we estimate probability distributions for these projections for the SSPs using Gaussian Process emulation of the ice sheet and glacier model ensembles. We model the sea level contribution as a function of global mean surface air temperature forcing and (for the ice sheets) model parameters, with the 'nugget' allowing for multi-model structural uncertainty. Approximate independence of ice sheet and glacier models is assumed, because a given model responds very differently under different setups (such as initialisation). We find that limiting global warming to 1.5&#176;C would halve the land ice contribution to 21st century sea level rise, relative to current emissions pledges: the median decreases from 25 to 13 cm sea level equivalent (SLE) by 2100. However, the Antarctic contribution does not show a clear response to emissions scenario, due to competing processes of increasing ice loss and snowfall accumulation in a warming climate. However, under risk-averse (pessimistic) assumptions for climate and Antarctic ice sheet model selection and ice sheet model parameter values, Antarctic ice loss could be five times higher, increasing the median land ice contribution to 42 cm SLE under current policies and pledges, with the 95th percentile exceeding half a metre even under 1.5&#176;C warming. Gaussian Process emulation can therefore be a powerful tool for estimating probability density functions from multi-model ensembles and testing the sensitivity of the results to assumptions.

The transient sensitivity of sea level rise

10.5194/egusphere-egu2020-7084 ◽

2020 ◽

Author(s):

Aslak Grinsted ◽

Jens Hesselbjerg Christensen

Keyword(s):

Surface Temperature ◽

Sea Level Rise ◽

Sea Level ◽

Rate Of Change ◽

Expert Elicitation ◽

Coastal Communities ◽

Observational Period ◽

Sea Levels ◽

Global Mean Surface Temperature ◽

We are warming our planet, and sea levels are rising as oceans expand and ice on land melts. This instigates a threat to coastal communities and ecosystems, and there is an urgent need for sea level predictions encompassing all known uncertainties to plan for it. Comprehensive assessments have concluded that sea level is unlikely to rise by more than about 1.1m this century but with further increase beyond 2100. However, some studies conclude that considerably greater sea level rise could be realised and an expert elicitation assign a substantially higher likelihood to this scenario. Here, we show that models used to assess future sea level in AR5 & SROCC have a lower sea level sensitivity than inferred from observations. By analyzing mean rate of change in sea level (not sea level itself), we identify a near linear relationship with global mean surface temperature in both model projections, and in observations. The model projections fall below expectations from the more recent observational period. This comparison suggests that the likely range of sea level projections in IPCC AR5 and SROCC would be too low.

Sea Level Rise and Impacts on Maritime Zones and Limits

The Korean Journal of International and Comparative Law ◽

10.1163/22134484-12340077 ◽

2017 ◽

Vol 5 (1) ◽

pp. 5-35 ◽

Cited By ~ 1

Author(s):

David Freestone ◽

Davor Vidas ◽

Alejandra Torres Camprubí

Keyword(s):

International Law ◽

Sea Level Rise ◽

Sea Level ◽

Regional Pattern ◽

Intergovernmental Panel ◽

Regional Sea Level ◽

International Legal System ◽

Future Work ◽

Global Mean ◽

Regional Sea Level Change

As the oceans warm and ice melts, the Intergovernmental Panel on Climate Change (ipcc) in its Fifth Assessment Report (AR5) now predicts a global average sea level rise of up to one meter by 2100. AR5 also emphasizes that sea level rise will have “a strong regional pattern, with some places experiencing significant deviations of local and regional sea level change from the global mean change.” These predictions pose serious and possibly existential threats to the inhabitants of low-lying islands and coastal areas, and pose challenges for the international legal system to respond in an orderly and humane way to these novel situations. In 2012, the International Law Association (ila) established a new Committee to look specifically at these issues. This article looks at the work undertaken by the Committee to date regarding the law of the sea aspects of its mandate and identifies some considerations for its future work.

Ice sheet contributions to future sea-level rise from structured expert judgment

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1817205116 ◽

2019 ◽

Vol 116 (23) ◽

pp. 11195-11200 ◽

Cited By ~ 104

Author(s):

Jonathan L. Bamber ◽

Michael Oppenheimer ◽

Robert E. Kopp ◽

Willy P. Aspinall ◽

Roger M. Cooke

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Ice Sheet ◽

Predictive Capability ◽

Intergovernmental Panel ◽

Process Understanding ◽

Temperature Scenario ◽

Global Mean Sea Level ◽

Observational Record ◽

Despite considerable advances in process understanding, numerical modeling, and the observational record of ice sheet contributions to global mean sea-level rise (SLR) since the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change, severe limitations remain in the predictive capability of ice sheet models. As a consequence, the potential contributions of ice sheets remain the largest source of uncertainty in projecting future SLR. Here, we report the findings of a structured expert judgement study, using unique techniques for modeling correlations between inter- and intra-ice sheet processes and their tail dependences. We find that since the AR5, expert uncertainty has grown, in particular because of uncertain ice dynamic effects. For a +2 °C temperature scenario consistent with the Paris Agreement, we obtain a median estimate of a 26 cm SLR contribution by 2100, with a 95th percentile value of 81 cm. For a +5 °C temperature scenario more consistent with unchecked emissions growth, the corresponding values are 51 and 178 cm, respectively. Inclusion of thermal expansion and glacier contributions results in a global total SLR estimate that exceeds 2 m at the 95th percentile. Our findings support the use of scenarios of 21st century global total SLR exceeding 2 m for planning purposes. Beyond 2100, uncertainty and projected SLR increase rapidly. The 95th percentile ice sheet contribution by 2200, for the +5 °C scenario, is 7.5 m as a result of instabilities coming into play in both West and East Antarctica. Introducing process correlations and tail dependences increases estimates by roughly 15%.

Climate-change–driven accelerated sea-level rise detected in the altimeter era

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1717312115 ◽

2018 ◽

Vol 115 (9) ◽

pp. 2022-2025 ◽

Cited By ~ 261

Author(s):

R. S. Nerem ◽

B. D. Beckley ◽

J. T. Fasullo ◽

B. D. Hamlington ◽

D. Masters ◽

...

Keyword(s):

Climate Change ◽

Sea Level Rise ◽

Sea Level ◽

Altimeter Data ◽

Intergovernmental Panel ◽

Mean Sea Level ◽

Simple Extrapolation ◽

Global Mean Sea Level ◽

Satellite Altimeter Data ◽

Using a 25-y time series of precision satellite altimeter data from TOPEX/Poseidon, Jason-1, Jason-2, and Jason-3, we estimate the climate-change–driven acceleration of global mean sea level over the last 25 y to be 0.084 ± 0.025 mm/y2. Coupled with the average climate-change–driven rate of sea level rise over these same 25 y of 2.9 mm/y, simple extrapolation of the quadratic implies global mean sea level could rise 65 ± 12 cm by 2100 compared with 2005, roughly in agreement with the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (AR5) model projections.

Contribution of Land Water Storage Change to Regional Sea-Level Rise Over the Twenty-First Century

Frontiers in Earth Science ◽

10.3389/feart.2021.627648 ◽

2021 ◽

Vol 9 ◽

Author(s):

Sitar Karabil ◽

Edwin H. Sutanudjaja ◽

Erwin Lambert ◽

Marc F. P. Bierkens ◽

Roderik S. W. Van de Wal

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Climate Models ◽

Sea Level Change ◽

First Century ◽

Level Change ◽

Regional Sea Level ◽

Twenty First Century ◽

Land Water ◽

Change in Land Water Storage (LWS) is one of the main components driving sea-level rise over the twenty-first century. LWS alteration results from both human activities and climate change. Up to now, all components to sea-level change are usually quantified upon a certain climate change scenario except land water changes. Here, we propose to improve this by analyzing the contribution of LWS to regional sea-level change by considering five Coupled Model Intercomparison Project Phase 5 (CMIP5) climate models forced by three different Representative Concentration Pathway (RCP) greenhouse gas emission scenarios. For this analysis, we used LWS output of the global hydrological and water resources model, PCR-GLOBWB 2, in order to project regional sea-level patterns. Projections of ensemble means indicate a range of LWS-driven sea-level rise with larger differences in projections among climate models than between scenarios. Our results suggest that LWS change will contribute around 10% to the projected global mean sea-level rise by the end of twenty-first century. Contribution of LWS to regional sea-level rise is projected to be considerably larger than the global mean over several regions, up to 60% higher than global average of LWS-driven sea-level rise, including the Pacific islands, the south coast of Africa and the west coast of Australia.

A modified impulse-response representation of the global response to carbon dioxide emissions

10.5194/acp-2016-405 ◽

2016 ◽

Cited By ~ 1

Author(s):

Richard J. Millar ◽

Zebedee R. Nicholls ◽

Pierre Friedlingstein ◽

Myles R. Allen

Keyword(s):

Carbon Dioxide ◽

Simple Model ◽

State Dependence ◽

Linear Increase ◽

Global Temperature ◽

Intergovernmental Panel ◽

Transient Climate Response ◽

Complex Models ◽

Carbon Dioxide Co2

Abstract. Projections of the response to anthropogenic emission scenarios, evaluation of some greenhouse gas metrics and estimates of the social cost of carbon, often require a simple model that links emissions of carbon dioxide CO2 to atmospheric concentrations and global temperature changes. An essential requirement of such a model is to reproduce the behaviour of more complex models as well as an ability to sample their range of response in a transparent, accessible and reproducible form. Here we adapt the simple model of the Intergovernmental Panel on Climate Change 5th Assessment Report (IPCC-AR5) to explicitly represent the state-dependence of the CO2 airborne fraction and reproduce several idealised experiments performed with more complex models. We find that a simple linear increase in 100-year integrated airborne fraction with cumulative carbon uptake and global temperature change is both necessary and sufficient to represent the response of the climate system to CO2 on a range of timescales and under a range of experimental designs. Quantified ranges of uncertainty (analogous to current assessed ranges in Equilibrium Climate Sensitivity and Transient Climate Response) in integrated airborne fraction over the 21st century under a representative mitigation scenario, and an assessed range in how much this quantity may have changed relative to pre-industrial conditions, would be valuable in future scientific assessments.

A STATISTICAL ANALYSIS AND PREDICTION OF CARBON DIOXIDE EMISSION IN HIMACHAL PRADESH, PUNJAB AND HARYANA STATES OF INDIA

Ensemble ◽

10.37948/ensemble-2020-0202-a001 ◽

2021 ◽

Vol 2 (1) ◽

pp. 1-10

Author(s):

Kartick Mondal ◽

◽

Sudipta Sinha ◽

Pijush Basak ◽

D P Goswami ◽

...

Keyword(s):

Carbon Dioxide ◽

Global Warming ◽

Carbon Dioxide Emission ◽

Himachal Pradesh ◽

Rate Of Change ◽

Least Square ◽

Evolutionary Trend ◽

Fourth Degree ◽

Instantaneous Rate

The universe is facing heavily the evil effects of Global warming, which is a burning issue today. With the advancement of civilization, new industries have been set-up to enhance production as per the need of society along with the population explosion. India is familiar as a developing country in the world, and at present, India has a significant contribution to the augmentation of Greenhouse Gases in the environment, which induces global warming. Global warming has serious effects of worsening the environment. It causes the melting of ice, extinction of species, prevalance of several fatal diseases, loss of biodiversity etc. In this paper, we develop a statistical model that analyzes and predicts the trend of emission of Carbon dioxide in Himachal Pradesh, Punjab, and Haryana. For this purpose, we have considered the dataset of 21 years of gas emission and tried to fit a fourth-degree polynomial curve by the least square method. We have tried to sketch a comparative scenario of carbon-dioxide emissions in the chosen states along with the forecast of the long-term evolutionary trend of the emission. The Instantaneous Rate of Change (IROC)analysis has been employed for this purpose. The efficacies of the model have been tested by residual analysis, coefficient of determination R2, and adjusted R2.