Geen diatitel

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The use of CHALLENGE datain climate change
detection claimsAlbert Klein Tank, KNMI
Source CRU/MetOffice, 2004
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Recent warming also observed over Europe
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• Warming dominates in all seasons, except Autumn
  (bottom right)

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• Climate change detection/attribution
• At the global scale most of the warming observed
  over the last 50 years is attributable to human
  activities.

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• Climate change detection/attribution
• At the global scale most of the warming observed
  over the last 50 years is attributable to human
  activities.
• At the continental scale (Europe), the
  attribution of the observed warming trends to
  human influence is not (yet) firmly settled due
  to the larger natural variability.

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• Climate change detection/attribution
• At the global scale most of the warming observed
  over the last 50 years is attributable to human
  activities.
• At the continental scale (Europe), the
  attribution of the observed warming trends to
  human influence is not (yet) firmly settled due
  to the larger natural variability.
• Anthropogenic signals have not yet been
  positively detected at all in series of extreme
  events, despite their obvious relevance for
  society.

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• Climate change detection/attribution
• At the global scale most of the warming observed
  over the last 50 years is attributable to human
  activities.
• At the continental scale (Europe), the
  attribution of the observed warming trends to
  human influence is not (yet) firmly settled due
  to the larger natural variability.
• Anthropogenic signals have not yet been
  positively detected at all in series of extreme
  events, despite their obvious relevance for
  society.
• We use CHALLENGE data to investigatewhether
  changes in the frequency ofmodest temperature
  extremes inEurope (expressed by T90-T10) area
  possible fingerprint of human influence.

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European window CHALLENGE data
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European station data
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• Spring change in T90-T10 trends (left) natural
  variability (right)

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• Summer change in T90-T10 trends (left) natural
  variability (right)

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• Autumn change in T90-T10 trends (left) natural
  variability (right)

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• Take-away messages
• Some of the characteristics of the recent warming
  in Europe provide a possible fingerprint of human
  influence, because they are different from the
  estimated patterns associated with natural
  temperature variability.
• Similar differences are seen in CHALLENGE between
  the patterns in the future greenhouse warming
  simulations and the current climate simulations.
• The advantage of the CHALLENGE data is that
  natural variability is explicitly accounted for
  in the ensemble of 62 climate model simulations.