Transcript Geen diatitel

The use of CHALLENGE data
in climate change detection claims
Albert Klein Tank, KNMI
Source: CRU/MetOffice, 2004
Recent warming also observed over Europe
Warming dominates in all seasons, except Autumn (bottom right)
Climate change detection/attribution:
 At the global scale most of the warming observed over the
last 50 years is attributable to human activities.
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.
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.
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 investigate
whether changes in the frequency of
modest temperature extremes in
Europe (expressed by T90-T10) are
a possible fingerprint of human influence.
European window CHALLENGE data
European station data
Spring change in T90-T10: trends (left) – natural variability (right)
Summer change in T90-T10: trends (left) – natural variability (right)
Autumn change in T90-T10: trends (left) – natural variability (right)
Take-away messages:
1.
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.
2.
Similar differences are seen in CHALLENGE between the
patterns in the future greenhouse warming simulations
and the current climate simulations.
3.
The advantage of the CHALLENGE data is that natural
variability is explicitly accounted for in the ensemble of
62 climate model simulations.