Hanley does a fantastic job of distinguishing between weather and climate, and stressing that we can't yet
attribute extreme events to specific causes while acknowledging that this summer's wild weather fits with IPCC predictions and will become a lot more common in the future.
Agreed that the marriage between climatology and synoptic dynamics is important, and is a sorely missing ingredient in attempts to
attribute extreme events to AGW.
In the science sessions in the afternoon, there was some good talks related to
attributing extreme events including Marty Hoerling discussing the Moscow heat wave and a very different perspective from the cpdn group in Oxford.
Nature has an interesting editorial this week on the state of the science for
attributing extreme events.
Not exact matches
«This new way of viewing the problem could be a game changer in the attribution of
extreme events by providing a framework to quantify the portion of the damage that can be
attributed to climate change — even for
events that themselves can not be directly
attributed to climate change using traditional methods,» continues Hammerling.
Normally, studies trying to
attribute climate change to
extreme events are published much later after the
event, noted Karoly.
Scientific confidence for
attributing extreme weather
events is a three - legged stool, said Titley.
The committee identified research priorities to further enhance the scientific community's ability to
attribute specific
extreme weather
events to climate change.
The committee found that scientists can now confidently
attribute some heat waves and cold
events, and to a lesser degree droughts and
extreme rainfall, to human - caused climate change.
What this report is saying is that we can
attribute an increased magnitude or frequency of some
extreme weather
events to climate change,» said David Titley, professor of practice in Penn State's Department of Meteorology and founding director of Penn State's Center for Solutions to Weather and Climate Risk, who chaired the committee that wrote the report.
«In the past, many scientists have been cautious of
attributing specific
extreme weather
events to climate change.
To
attribute any specific
extreme weather
event — such as the downpours that caused flooding in Pakistan or Australia, for example — requires running such computer models thousands of times to detect any possible human impact amidst all the natural influences on a given day's weather.
As a quote
attributed to mathematician Benoît Mandelbrot put it, «Even though economics is a very old subject, it has not truly come to grips with the main difficulty, which is the inordinate practical importance of a few
extreme events.»
«In the past, a typical climate scientist's response to questions about climate change's role in any given
extreme weather
event was, «We can not
attribute any single
event to climate change.»
This is addressed by evaluating change in global or large - scale patterns in the frequency or intensity of
extremes (e.g., observed widespread intensification of precipitation
extremes attributed to human influence, increase in frequency and intensity of hot
extremes) and by
event attribution methods.
The
Extremes Grand Challenge is organised around four over arching themes (Document, Understand, Simulate,
Attribute) with a main focus on four core
events (Heavy Precipitation, Heatwave, Drought, Storm).
«For a long time, the standard answer of climate scientists to an
extreme event was «we can't
attribute single
events to climate change», which when you think about it is an incredibly naive position.
Single
extreme events can not be simply and directly
attributed to anthropogenic climate change, as there is always a finite chance the
event in question might have occurred naturally.
So while scientists can not
attribute Hurricane Katrina, drought, or other
extreme weather
events to climate change, they can say climate change increases the risk of these occurring.
Imagine, say, a bell - shaped curve based on the null hypothesis that climate change is not happening (and not having an impact on increasing
extreme weather
events), and there is this really long tail out to infinity; and supposing we get an off - the - charts category 7 hurricane in January, we still can not
attribute it or its extra intensity or unusual seasonality to climate change, even if there is only a one in kazillion chance it might occur without climate change having an effect — that is, it is way out there in the very tiny tail of this null hypothesis curve that fades out into infinity — the tail that says, afterall, anything's possible.
When they get to.05 on my null (95 % confidence that ACC is not happening, and
extreme events can not in any way at all be
attributed to ACC), then I will still continue to mitigate, bec it saves me lots of money.
«Global economic losses of tens of billions of dollars are
attributed to
extremes of ENSO (i.e., El Nino and La Nina), suggesting that these
events disproportionately trigger socioeconomic disasters on the global scale.
While it is «likely» that anthropogenic influences are behind the changes in cold days and warm days, there is only «medium confidence» that they are behind changes in
extreme rainfall
events, and «low confidence» in
attributing any changes in tropical cyclone activity to greenhouse gas emissions or anything else humanity has done.
I understand scientists can not
attribute a single
extreme event to GW; it may in God - only - knows reality be due to GW, but scientists don't have the tools to make such a claim.
But if it's sufficiently
extreme, it would be easier to
attribute it to physical conditions if you can simulate the
event.
No single weather
event can be
attributed to climate change, but a warming climate does load the dice in favor of heavier
extreme precipitation
events.
In the past, a typical climate scientist's response to questions about climate change's role in any given
extreme weather
event was, «We can not
attribute any single
event to climate change.»
In recent decades, this warming was accompanied by the constant rising of the sea level, and it is also hard not to relate it with the rise in
extreme weather
events, regardless of the fact that we can not
attribute a scientifically determined cause to each phenomenon in particular.
A wide range of
extreme weather
events is expected in most regions even with an unchanging climate, so it is difficult to
attribute any individual
event to a change in the climate.
The phrase, oft - repeated after
extreme weather
events «no single weather
event can be
attributed to climate change» applies to Haiyan as it does to any
extreme weather.
When an
extreme climate
event takes place, a range of users would like to know as soon as possible not only how rare this particular
event is but also whether it could be
attributed to climate change or if, instead, it is part of the climate variability one would expect in the absence of climate change.
That is a true statement, it is not possible at this time to accurately
attribute extreme weather
events to AGW.
little evidence that supports an increase in
extreme weather
events that can be
attributed to humans...
A question of interest across many disciplines concerns the extent to which such
extreme events can be
attributed to anthropogenic influences.
Hence, the 2012 Arctic sea ice minimum provides a counterexample to the often - quoted idea that individual
extreme events can not be
attributed to human influence.
The link between adverse impacts such as more wildfires, ecosystem changes,
extreme weather
events etc. and their mitigation by reducing greenhouse gas emissions hinges on detecting unusual
events for at least the past century and then actually
attributing them to human caused warming.
Erasing empirical temperature records,
attributing extreme weather
events to global warming without any data, yet you probably find their actions to be fine, regardless of the harm they have done.
Look At the Trends in
Extreme Weather and See the State of the World BY EDITOR OF THE FABIUS MAXIMUS WEBSITE ON 5 APRIL 2017 • Summary: Climate activists make bold claims about
extreme weather caused by our CO2 emissions,
attributing most big weather
events to CO2's influence.
Studies to assess whether
extreme events can be
attributed to climate change are published, with contributions from weatherathome data.
Scientists» ability to
attribute individual
extreme weather
events to climate change (or not) continues to grow.
One of the first studies to
attribute a single
extreme weather
event to climate change was published just over a decade ago.
blockquoteSingle
extreme events can not be simply and directly
attributed to anthropogenic climate change, as there is always a finite chance the
event in question might have occurred naturally.
While it is very difficult to
attribute individual weather
events to global warming, we do know that climate change will «load the dice» and result in more frequent
extreme weather
events.
The significance of
attributing the role of climate change in an
extreme event comes from situating that hazard in the context of long term climate change for a country or region, and thus creating a robust narrative for decision - makers and the public around the degree to which a disaster of this type will represent the «new normal».
Key remaining uncertainties relate to the precise magnitude and nature of changes at global, and particularly regional, scales, and especially for
extreme events and our ability to simulate and
attribute such changes using climate models.
Although individual hurricanes can not be directly
attributed to climate change, Hurricanes Irene and Sandy nevertheless provided «teachable moments» by demonstrating the region's vulnerability to
extreme weather
events and the potential for adaptation to reduce impacts.
According to John Holdren, director of the White House Office of Science and Technology Policy, Obama will emphasize the current scientific understanding of how, while no single weather
event can be
attributed to climate change, a warming climate can make things like drought more
extreme:
«Aggregate mortality
attributed to all
extreme weather
events globally has declined by more than 90 % since the 1920s, in spite of a four-fold rise in population and much more complete reporting of such
events,» the report noted.
In the case of climate change, its such an all pervasive theme in media, one constantly has to check one's tendency to
attribute any
extreme weather
event to it.
However, because of issues related to data quality, the low frequency of
extreme event impacts, limited length of the time series, and various societal factors present in the disaster loss record, it is still not possible to determine the portion of the increase in damages that might be
attributed to climate change brought about by greenhouse gas emissions (S1).