---
chapter:
  doi: 10.7930/J0WH2N54
  identifier: projections
  number: 4
  report_identifier: climate-science-special-report
  sort_key: 6
  title: 'Climate Models, Scenarios, and Projections'
  url: https://science2017.globalchange.gov/chapter/4/
chapter_identifier: projections
cited_by: []
confidence: 'The statement has <em>high confidence</em> in the sign of future change and <em>medium confidence</em> in the amount of warming, based on the estimate of committed warming at constant atmospheric concentrations from Collins et al.<tbib>b3bbc7b5-067e-4c23-8d9b-59faee21e58e</tbib> based on Meehl et al.<tbib>eff5ce0d-c403-455b-9358-98be45351c7b</tbib> for a hypothetical scenario where concentrations in the atmosphere were fixed at a known level.'
contributors: []
evidence: 'The basic physics underlying the impact of human emissions on global climate, and the role of climate sensitivity in moderating the impact of those emissions on global temperature, has been documented since the 1800s in a series of peer-reviewed journal articles that is summarized in a collection titled, “The Warming Papers: The Scientific Foundation for the Climate Change Forecast”.<tbib>eff1b5aa-a791-4a23-a595-92ae2c629e77</tbib> </br></br> The estimate of committed warming at constant atmospheric concentrations is based on IPCC AR5 WG1, Chapter 12, section 12.5.2,<tbib>b3bbc7b5-067e-4c23-8d9b-59faee21e58e</tbib> page 1103 which is in turn derived from AR4 WG1, Chapter 10, section 10.7.1,<tbib>eff5ce0d-c403-455b-9358-98be45351c7b</tbib> page 822.'
files: []
gcmd_keywords: []
href: https://data.globalchange.gov/report/climate-science-special-report/chapter/projections/finding/key-finding-4-1.yaml
identifier: key-finding-4-1
ordinal: 1
parents:
  - activity_uri: ~
    label: 'figure -.2: Confidence / Likelihood'
    note: ''
    publication_type_identifier: figure
    relationship: prov:wasDerivedFrom
    url: /report/climate-science-special-report/chapter/front-matter/figure/confidence---likelihood
process: The key finding is based on the basic physical principles of radiative transfer that have been well established for decades to centuries; the amount of estimated warming for this hypothetical scenario is derived from Collins et al.<tbib>b3bbc7b5-067e-4c23-8d9b-59faee21e58e</tbib> which is in turn based on Meehl et al.<tbib>eff5ce0d-c403-455b-9358-98be45351c7b</tbib> using CMIP3 models.
references:
  - href: https://data.globalchange.gov/reference/b3bbc7b5-067e-4c23-8d9b-59faee21e58e.yaml
    uri: /reference/b3bbc7b5-067e-4c23-8d9b-59faee21e58e
  - href: https://data.globalchange.gov/reference/eff1b5aa-a791-4a23-a595-92ae2c629e77.yaml
    uri: /reference/eff1b5aa-a791-4a23-a595-92ae2c629e77
  - href: https://data.globalchange.gov/reference/eff5ce0d-c403-455b-9358-98be45351c7b.yaml
    uri: /reference/eff5ce0d-c403-455b-9358-98be45351c7b
regions: []
report_identifier: climate-science-special-report
statement: 'If greenhouse gas concentrations were stabilized at their current level, existing concentrations would commit the world to at least an additional 1.1°F (0.6°C) of warming over this century relative to the last few decades (<em>high confidence</em> in continued warming, <em>medium confidence</em> in amount of warming).'
uncertainties: The uncertainty in projected change under a commitment scenario is low and primarily the result of uncertainty in climate sensitivity. This key finding describes a hypothetical scenario that assumes all human-caused emissions cease and the Earth system responds only to what is already in the atmosphere.
uri: /report/climate-science-special-report/chapter/projections/finding/key-finding-4-1
url: ~