Abrupt Impacts of Climate Change Anticipating Surprises (2013) / Chapter Skim
Currently Skimming:
Summary
Summary
Pages 1-18
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 1... ...
Some abrupt climate changes are already underway, including the rapid decline of Arctic sea ice over the past decade due to warmer polar temperatures. In addition there are many parts of the climate system that have been thought to be possibly prone to near-future abrupt change that would trigger significant impacts at the regional and global scale.
|
From page 2... ...
Those populations that cannot do so quickly enough will be in danger of extinction. In addition, human infrastructure is built with certain expectations of useful life expectancy, but even gradual climate changes may trigger abrupt thresholds in their utility, such as rising sea levels surpassing sea walls or thawing permafrost destabilizing pipelines, buildings, and roads.
|
From page 3... ...
. This rapid reduction in Arctic sea ice already qualifies as an abrupt change with substantial decreases in ice extent occurring within the past several decades.
|
From page 4... ...
The Arctic is also a region of increasing economic importance for a diverse range of stakeholders, and reductions in Arctic sea ice will bring new legal and political challenges as navigation routes for commercial shipping open and marine access to the region increases for offshore oil and gas development, tourism, fishing and other activities. Understanding and predicting future changes in Arctic sea ice will require maintained and expanded observations of sea ice thickness and extent, including satellite-based measurements.
|
From page 5... ...
Species like polar bears are at risk because they depend on sea ice to facilitate their hunting of seals and Arctic sea ice conditions are changing rapidly. Other species are prone to extinction as changing climate causes their habitats to alter such that growth, development, or reproduction of constituent individuals are inhibited.
|
From page 6... ...
The figure shows two methods of calculating the velocity of climate change for different time periods at the end of this century. The top panel shows the velocity in terms of nearest equivalent temperature, i.e., the climate change velocity in the CMIP5 RCP8.5 ensemble, calculated by identifying the closest location (to each grid point)
|
From page 7... ...
The rates of ice and water loss from ice stored on land directly affect the speed of sea level rise, which in turn directly affects coastal communities. Of greatest concern among the stocks of land ice are those glaciers whose bases are well below sea level, which includes most of West Antarctica, as well as smaller parts of East Antarctica and Greenland.
|
From page 8... ...
Improved understanding of key physical processes and inclusion of them in models, together with improved projections of changes in the surrounding ocean, are required to notably reduce uncertainties and to better quantify worst-case scenarios. Because large uncertainties remain, the Committee judges an abrupt change in the WAIS within this century to be plausible, with an unknown although probably low probability.
|
From page 9... ...
This circulation pattern plays a critical role in the global transport of oceanic heat, salt, and carbon. Paleoclimate evidence of temperature and other changes recorded in North Atlantic Ocean sediments, Greenland ice cores and other archives suggest that the AMOC abruptly shut down and restarted in the past -- possibly triggered by large pulses of glacial meltwater or gradual meltwater supplies crossing a threshold -- raising questions about the potential for abrupt change in the future.
|
From page 10... ...
Basic research is required to assess the long-term stability of currently frozen Arctic and sub-Arctic soil stocks, and of the possibility of increasing the release of methane gas bubbles from currently frozen marine and terrestrial sediments, as temperatures rise. Summary of Abrupt Climate Changes and Abrupt Climate Impacts In addition to the abrupt changes described in the sections above, the Committee examined a number of other possible changes.
|
From page 11... ...
Identifying key vulnerabilities can help guide efforts to increase resiliency and avoid large damages from abrupt change in the climate system, or in abrupt impacts of gradual changes in the climate system, and facilitate more informed decisions on the proper balance between mitigation and adaptation. With adequate scientific monitoring and study of these potential changes to the climate system, the probability that society can anticipate future abrupt climate changes and impacts will be substantially increased.
|
From page 12... ...
THE WAY FORWARD Scientific understanding of abrupt changes in the physical climate system and abrupt impacts of climate change has steadily advanced over the past couple of decades. Owing to these scientific advances, some of the possible abrupt climate change mechanisms whose probability of occurrence was previously poorly known are now understood to be unlikely during this century -- these include a sudden shutdown 12
|
From page 13... ...
Although there is still much to learn about abrupt climate change and abrupt climate impacts, to willfully ignore the threat of abrupt change could lead to more costs, loss of life, suffering, and environmental degradation. The time is here to be serious about the threat of tipping points so as to better anticipate and prepare ourselves for the inevitable surprises.
|
From page 14... ...
• Southward shift of tropical • Monitoring of overturning at rain belts other latitudes • Large disruptions to local • Enhanced understanding of marine ecosystems drivers of AMOC variability • Ocean and atmospheric temperature and circulation changes • Changes in ocean's ability to store heat and carbon Sea level rise (SLR) from Moderate Low2 High High • Maintenance and expansion Abrupt Changes in the Ocean ocean thermal expansion increase in of monitoring of sea level • Coastal inundation sea level rise (tide gauges and satellite • Storm surges more likely to data)
|
From page 15... ...
) detected oxygen content, pH, and • Threats to aerobic marine life temperature • Release of nitrous oxide • Improved understanding gas -- a potent greenhouse and modeling of ocean gas -- to the atmosphere mixing • Improved understanding of microbial processes in OMZs Changes to patterns Trends not Low Moderate Low to • Maintaining continuous of climate variability detectable for Moderate records of atmospheric most patterns pressure and temperatures • Substantial surface weather of climate from both in-situ and changes throughout variability remotely sensed sources much of extratropics if the Exception • Assessing robustness extratropical jetstreams were is southern of circulation shifts in to shift abruptly annular individual ensemble mode -- members in climate change detectable simulations Abrupt Changes in the Atmosphere poleward shift • Developing theory on of middle circulation response to latitude anthropogenic forcing jetstream Increase in intensity, Detectable Moderate High High • Continued progress on frequency, and duration of increasing (Regionally understanding climate heat waves trends variable, dynamics • Increased mortality dependent • Increased focus on risk • Decreased labor capacity on soil assessment and resilience • Threats to food and water moisture)
|
From page 16... ...
Understanding Monitoring, etc.) Increasing release of Neutral trend Low High Moderate4 • Improved models of carbon stored in soils and to small trend hydrology/cryosphere permafrost in increasing interaction and ecosystem • of human- soil carbon response induced climate change3 release • Greater study of role of in rapid carbon release • Expanded borehole temperature monitoring networks • Enhanced satellite and ground-based monitoring of atmospheric methane concentrations at high latitudes Increasing release of Trend not Low5 Moderate Moderate6 • Field and model based methane from ocean clearly characterization of the Abrupt Changes at High Latitudes methane hydrates detected sediment column • of human- • Enhanced satellite and induced climate change ground-based monitoring of atmospheric methane concentrations at high latitudes Late-summer Arctic sea ice Strong trend High Very high High • Enhanced Arctic disappearance in decreasing observations, including • Large and irreversible effects sea ice cover atmosphere, sea ice, and on various components of ocean characteristics the Arctic ecosystem • Better monitoring and • Impacts on human society census studies of marine and economic development ecosystems in coastal polar regions • Improved large-scale • Implications for Arctic models that incorporate the shipping and resource evolving state of knowledge extraction • Potential to alter large-scale atmospheric circulation and its variability Winter Arctic sea ice Small trend Low Moderate High • Same as late summer disappearance (Decreasing Arctic sea ice • Same as late summer Arctic but not disappearance above sea ice disappearance disappearing)
|
From page 17... ...
multiply extinction intensity • Improved monitoring of key species 1 Change could be either abrupt or non-abrupt. 2 To clarify, the Committee assesses the near-term outlook that sea level will rise abruptly before the end of this century as Low; this is not in contradiction to the assessment that sea level will continue to rise steadily with estimates of between 0.26 and 0.82 m by the end of this century (IPCC, 2013)
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.