scholarly journals Past climates inform our future

Science ◽  
2020 ◽  
Vol 370 (6517) ◽  
pp. eaay3701
Author(s):  
Jessica E. Tierney ◽  
Christopher J. Poulsen ◽  
Isabel P. Montañez ◽  
Tripti Bhattacharya ◽  
Ran Feng ◽  
...  
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Model Evaluation ◽  
Future Climate Change ◽  
Earth System ◽  
High Carbon ◽  
The Earth ◽  
The World ◽  
Earth System Models ◽  
High Carbon Dioxide

As the world warms, there is a profound need to improve projections of climate change. Although the latest Earth system models offer an unprecedented number of features, fundamental uncertainties continue to cloud our view of the future. Past climates provide the only opportunity to observe how the Earth system responds to high carbon dioxide, underlining a fundamental role for paleoclimatology in constraining future climate change. Here, we review the relevancy of paleoclimate information for climate prediction and discuss the prospects for emerging methodologies to further insights gained from past climates. Advances in proxy methods and interpretations pave the way for the use of past climates for model evaluation—a practice that we argue should be widely adopted.

scholarly journals Earth System Model Evaluation Tool (ESMValTool) v2.0 – an extended set of large-scale diagnostics for quasi-operational and comprehensive evaluation of Earth system models in CMIP

2020 ◽  
Vol 13 (7) ◽  
pp. 3383-3438 ◽  
Author(s):  
Veronika Eyring ◽  
Lisa Bock ◽  
Axel Lauer ◽  
Mattia Righi ◽  
Manuel Schlund ◽  
...  
Keyword(s):  
Model Evaluation ◽  
Large Scale ◽  
Performance Metrics ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Evaluation Tool ◽  
The Earth ◽  
And Performance ◽  
Earth System Models

Abstract. The Earth System Model Evaluation Tool (ESMValTool) is a community diagnostics and performance metrics tool designed to improve comprehensive and routine evaluation of Earth system models (ESMs) participating in the Coupled Model Intercomparison Project (CMIP). It has undergone rapid development since the first release in 2016 and is now a well-tested tool that provides end-to-end provenance tracking to ensure reproducibility. It consists of (1) an easy-to-install, well-documented Python package providing the core functionalities (ESMValCore) that performs common preprocessing operations and (2) a diagnostic part that includes tailored diagnostics and performance metrics for specific scientific applications. Here we describe large-scale diagnostics of the second major release of the tool that supports the evaluation of ESMs participating in CMIP Phase 6 (CMIP6). ESMValTool v2.0 includes a large collection of diagnostics and performance metrics for atmospheric, oceanic, and terrestrial variables for the mean state, trends, and variability. ESMValTool v2.0 also successfully reproduces figures from the evaluation and projections chapters of the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) and incorporates updates from targeted analysis packages, such as the NCAR Climate Variability Diagnostics Package for the evaluation of modes of variability, the Thermodynamic Diagnostic Tool (TheDiaTo) to evaluate the energetics of the climate system, as well as parts of AutoAssess that contains a mix of top–down performance metrics. The tool has been fully integrated into the Earth System Grid Federation (ESGF) infrastructure at the Deutsches Klimarechenzentrum (DKRZ) to provide evaluation results from CMIP6 model simulations shortly after the output is published to the CMIP archive. A result browser has been implemented that enables advanced monitoring of the evaluation results by a broad user community at much faster timescales than what was possible in CMIP5.

Consistent global responses of marine ecosystems to future climate change across the IPCC AR5 earth system models

2014 ◽  
Vol 45 (5-6) ◽  
pp. 1253-1280 ◽  
Author(s):  
Anna Cabré ◽  
Irina Marinov ◽  
Shirley Leung
Keyword(s):  
Climate Change ◽  
Marine Ecosystems ◽  
Future Climate ◽  
Future Climate Change ◽  
Earth System ◽  
System Models ◽  
Earth System Models

Environmental Security and Climate Change

2010 ◽  
Author(s):  
Simon Dalby
Keyword(s):  
Climate Change ◽  
Environmental Change ◽  
Security Policy ◽  
Growth Failure ◽  
Environmental Security ◽  
Peace Building ◽  
Future Climate Change ◽  
Fragile States ◽  
Earth System ◽  
The Earth

Environmental security focuses on the ecological conditions necessary for sustainable development. It encompasses discussions of the relationships between environmental change and conflict as well as the larger global policy issues linking resources and international relations to the necessity for doing both development and security differently. Climate change has become an increasingly important part of the discussion as its consequences have become increasingly clear. What is not at all clear is in what circumstances climate change may turn out to be threat multiplier leading to conflict. Earth system science findings and the recognition of the scale of human transformations of nature in what is understood in the 21st century to be a new geological epoch, the Anthropocene, now require environmental security to be thought of in terms of preventing the worst dangers of fragile states being unable to cope with the stresses caused by rapid environmental change or perhaps the economic disruptions caused by necessary transitions to a post fossil fueled economic system. But so far, at least, this focus on avoiding the worst consequences of future climate change has not displaced traditional policies of energy security that primarily ensure supplies of fossil fuels to power economic growth. Failure to make this transition will lead to further rapid disruptions of climate and add impetus to proposals to artificially intervene in the earth system using geoengineering techniques, which might in turn generate further conflicts from states with different interests in how the earth system is shaped in future. While the Paris Agreement on Climate Change recognized the urgency of tackling climate change, the topic has not become security policy priority for most states, nor yet for the United Nations, despite numerous policy efforts to securitize climate change and instigate emergency responses to deal with the issue. More optimistic interpretations of the future suggest possibilities of using environmental actions to facilitate peace building and a more constructive approach to shaping earth’s future.

Precautionary Politics: Principle and Practice in Confronting Environmental Risk. By Kerry Whiteside. Cambridge, MA: MIT Press, 2006. 198p. $50.00 cloth, $21.00 paper.

2009 ◽  
Vol 7 (1) ◽  
pp. 157-158
Author(s):  
Scott Barrett
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Large Scale ◽  
Hadron Collider ◽  
The Earth ◽  
New Knowledge ◽  
The World ◽  
Desert Regions ◽  
Mitigate Climate Change ◽  
Theoretical Risk

Here are two challenges that the world has had to face in 2008: 1) Construction of the Large Hadron Collider was recently completed. Experiments using this machine will yield new knowledge of a fundamental kind. There is also a theoretical risk, believed to be vanishingly small but not zero, that the machine could create a black hole capable of destroying the Earth. Should the machine be turned on? 2) Fertilizing “desert” regions of the oceans with iron is expected to stimulate phytoplankton growth, sucking carbon dioxide into the oceans and thus helping to mitigate climate change. It might also alter vital ocean ecosystems. To know the full consequences of ocean fertilization, large-scale experiments are needed. Should they be allowed?

Is large-scale terrestrial hydrological cycling well represented in Earth System Models?

2021 ◽  
Author(s):  
Navid Ghajarnia ◽  
Zahra Kalantari ◽  
Georgia Destouni
Keyword(s):  
Climate Change ◽  
Observational Data ◽  
Large Scale ◽  
Hydrological Cycle ◽  
Good Representation ◽  
Earth System ◽  
System Models ◽  
The World ◽  
Terrestrial Hydrology ◽  
Earth System Models

<p>This paper addresses how large-scale terrestrial water cycling is represented in the land surface schemes of Earth System Models (ESMs). Good representation is essential, for example in regional planning for climate change adaptation and in preparation for hydro-climatic extremes that have recently set records world-wide in devastating consequences for societies and deaths of thousands of people. ESMs provide simulations and projections for the climate system and its interactions with the terrestrial hydrological cycle, and are widely used to study and prepare for associated impacts of climate change. However, the reliability of ESMs is unclear with regard to their representation of large-scale terrestrial hydrology and its changes and interactions between its key variables‎. Despite being crucial for model realism, analysis of co-variations among terrestrial hydrology variables is still largely missing in ESM performance evaluations. To bridge this research gap, we have studied and identified large-scale co-variation patterns between soil moisture (SM) and the main freshwater fluxes of runoff (R), precipitation (P), and evapotranspiration (ET) from observational data and across 6405 hydrological catchments in different parts and climates of the world. Furthermore, we have compared the identified observation-based relationships with those emerging from ESMs and reanalysis products. Our results show that the most strongly correlated freshwater variables based on observational data are also the most misrepresented hydrological patterns in ESMs and reanalysis simulations. In particular, we find SM and R to have the generally strongest large-scale correlations according to the observation-based data, across the numerous studied catchments with widely different hydroclimatic characteristics. Compared to the SM-R correlation signals, the observation-based correlations are overall weaker for the commonly expected closer dependencies of: R on P; ET on P; SM on P; and ET on SM. Nevertheless, this strongest SM-R correlation and the P-R correlation are the most misrepresented hydrological patterns in reanalysis products and ESMs. Our results also show that ESM outputs can perform relatively well in simulating individual hydrological variables, while exhibiting essential inconsistencies in simulated co-variations between variables. Such investigations of large-scale terrestrial hydrology representation by ESMs can enhance our understanding of fundamental ESM biases and uncertainties while providing important insights for systematic ESM improvement with regard to the large-scale hydrological cycling over the world’s continents and regional land areas.</p>

scholarly journals Quantifying regional, time-varying effects of cropland and pasture on vegetation fire

2015 ◽  
Vol 12 (22) ◽  
pp. 6591-6604 ◽  
Author(s):  
S. S. Rabin ◽  
B. I. Magi ◽  
E. Shevliakova ◽  
S. W. Pacala
Keyword(s):  
Management Practices ◽  
Fire Regimes ◽  
Burned Area ◽  
Land Uses ◽  
Earth System ◽  
Monthly Basis ◽  
Global Estimate ◽  
The Earth ◽  
The World ◽  
Earth System Models

Abstract. The global extent of agriculture demands a thorough understanding of the ways it impacts the Earth system through the modification of both the physical and biological characteristics of the landscape as well as through emissions of greenhouse gases and aerosols. People use fire to manage cropland and pasture in many parts of the world, impacting both the timing and amount of fire. So far, much previous research into how these land uses affect fire regimes has focused on either individual small regions or global patterns at annual or decadal scales. Moreover, because pasture is not mapped globally at high resolution, the amount of fire associated with pasture has never been quantified as it has for cropland. The work presented here resolves the effects of agriculture – including pasture – on fire on a monthly basis for regions across the world, using globally gridded data on fire activity and land use at 0.25° resolution. The first global estimate of pasture-associated fire reveals that it accounts for over 40 % of annual burned area. Cropland, generally assumed to reduce fire occurrence, is shown to enhance or suppress fire at different times of year within individual regions. These results bridge important gaps in the understanding of how agriculture and associated management practices influence vegetation fire, enabling the next generation of vegetation and Earth system models more realistically incorporate these anthropogenic effects.

scholarly journals Emergent Constraints on Climate-Carbon Cycle Feedbacks

2019 ◽  
Vol 5 (4) ◽  
pp. 275-281 ◽  
Author(s):  
Peter M. Cox
Keyword(s):  
Climate Change ◽  
Carbon Cycle ◽  
Future Climate ◽  
Future Climate Change ◽  
Climate Projections ◽  
Earth System ◽  
Model Errors ◽  
The Earth ◽  
The Future ◽  
Emergent Constraints

Abstract Purpose of Review Feedbacks between CO2-induced climate change and the carbon cycle are now routinely represented in the Earth System Models (ESMs) that are used to make projections of future climate change. The inconclusion of climate-carbon cycle feedbacks in climate projections is an important advance, but has added a significant new source of uncertainty. This review assesses the potential for emergent constraints to reduce the uncertainties associated with climate-carbon cycle feedbacks. Recent Findings The emergent constraint technique involves using the full ensemble of models to find an across-ensemble relationship between an observable feature of the Earth System (such as a trend, interannual variation or change in seasonality) and an uncertain aspect of the future. Examples focussing on reducing uncertainties in future atmospheric CO2 concentration, carbon loss from tropical land under warming and CO2 fertilization of mid- and high-latitude photosynthesis are exemplars of these different types of emergent constraints. Summary The power of emergent constraints is that they use the enduring range in model projections to reduce uncertainty in the future of the real Earth System, but there are also risks that indiscriminate data-mining, and systematic model errors could yield misleading constraints. A hypothesis-driven theory-led approach can overcome these risks and also reveal the true promise of emergent constraints—not just as ways to reduce uncertainty in future climate change but also to catalyse advances in our understanding of the Earth System.

scholarly journals Collateral transgression of planetary boundaries due to climate engineering by terrestrial carbon dioxide removal

2016 ◽  
Author(s):  
Vera Heck ◽  
Jonathan F. Donges ◽  
Wolfgang Lucht
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Global Warming ◽  
Carbon Dioxide Removal ◽  
Earth System ◽  
Planetary Boundaries ◽  
Climate Engineering ◽  
Terrestrial Carbon ◽  
The Earth ◽  
Atmospheric Carbon

Abstract. The planetary boundaries framework as proposed by Rockström et al. (2009) provides guidelines for defining thresholds in environmental variables. Their transgression is likely to result in a shift in Earth system functioning away from the relatively stable Holocene state. As the climate change boundary is already transgressed, several climate engineering methods are discussed, aiming at a reduction of atmospheric carbon concentrations to control the Earth's energy balance. Terrestrial carbon dioxide removal (tCDR) via afforestation or bioenergy production with carbon capture and storage are part of most climate change mitigation scenarios that limit global warming to less than 2 °C. We analyse the co-evolutionary interaction of societal interventions via tCDR and the natural dynamics of the Earth's carbon cycle. Applying a conceptual modelling framework, we analyse how societal monitoring and management of atmospheric CO2 concentrations with the aim of staying within a "safe" level of global warming might influence the state of the Earth system with respect to other carbon-related planetary boundaries. Within the scope of our approach, we show that societal management of atmospheric carbon via tCDR can lead to a transgression of the planetary boundaries of land system change and ocean acidification. Our analysis indicates that the opportunities to remain in a desirable region within carbon-related planetary boundaries depend critically on the sensitivity and strength of the tCDR management system, as well as underlying emission pathways. While tCDR has the potential to ensure the Earth system's persistence within a carbon safe operating space under low emission pathways, this potential decreases rapidly for medium to high emission pathways.

scholarly journals Carbon cycle feedbacks and future climate change

2015 ◽  
Vol 373 (2054) ◽  
pp. 20140421 ◽  
Author(s):  
Pierre Friedlingstein
Keyword(s):  
Climate Change ◽  
Carbon Cycle ◽  
Positive Feedback ◽  
Future Climate ◽  
Future Climate Change ◽  
Earth System ◽  
System Models ◽  
New Findings ◽  
Tightly Coupled ◽  
Earth System Models

Climate and carbon cycle are tightly coupled on many timescales, from interannual to multi-millennial timescales. Observations always evidence a positive feedback, warming leading to release of carbon to the atmosphere; however, the processes at play differ depending on the timescales. State-of-the-art Earth System Models now represent these climate-carbon cycle feedbacks, always simulating a positive feedback over the twentieth and twenty-first centuries, although with substantial uncertainty. Recent studies now help to reduce this uncertainty. First, on short timescales, El Niño years record larger than average atmospheric CO 2 growth rate, with tropical land ecosystems being the main drivers. These climate-carbon cycle anomalies can be used as emerging constraint on the tropical land carbon response to future climate change. Second, centennial variability found in last millennium records can be used to constrain the overall global carbon cycle response to climatic excursions. These independent methods point to climate-carbon cycle feedback at the low-end of the Earth System Models range, indicating that these models overestimate the carbon cycle sensitivity to climate change. These new findings also help to attribute the historical land and ocean carbon sinks to increase in atmospheric CO 2 and climate change.

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