The Australian

NO ‘EMERGENCY’ SHOWN IN
CLIMATE RECORDS
GRAHAM LLOYD
An international study of major weather and extreme events
has found no evidence of a “climate emergency” in the
record to date.
The study by Italian scientists provides a long-term analysis
of heat, drought, floods, hurricanes, tornadoes and
ecosystem productivity and finds no clear positive trend of
extreme events.
The authors do not say that no action should be taken on
climate change but argue the issue should be placed in a
bigger context.
“Fearing a climate emergency without this being supported
by data, means altering the framework of priorities with
negative effects that could prove deleterious to our ability to
face the challenges of the future, squandering natural and
human resources in an economically difficult context,” the
report, published in European Physical Journal Plus, said.
The paper – “A critical assessment of extreme events trends
in times of global warming” – found the most robust global
changes in climate extremes are found in yearly values of
heatwaves, but it said global trends in heatwave intensity
were “not significant”.
Daily rainfall intensity and extreme precipitation frequency
were stationary.
Tropical cyclones show a “substantial temporal invariance”,
as do tornadoes.
The impact of warming on surface and wind speed remained
unclear.
The team, led by Gianluca Alimonti from the Italian National
Institute for Nuclear Physics and the University of Milan,
extended the analysis to include natural disasters, floods,
drought, ecosystem productivity and yields of the four main
crops (maize, rice, soybean and wheat).
“None of these response indicators show a clear positive
trend of extreme events,” the report said.
The authors said it was important to underline the difference
between statistical evidence of excess of events, with given
characteristic, and probabilistic calculation of anthropogenic
attribution of extreme events. The statistical evidence is
based on historical observations and tries to highlight
differences between these and recent observations or
possible trends as a function of time. “The anthropogenic
versus natural attribution of the origin of a phenomenon is
based on probabilistic models and makes reliance on
simulations that hardly reproduce the macro and
microphysical variables involved in it,” the researchers said.
“In conclusion, on the basis of observational data, the
climate crisis that, according to many sources, we are
experiencing today, is not evident yet.”
On floods, the report said: “Although evidence of an increase
in total annual precipitation is observed on a global level,
corresponding evidence for increases in flooding remains
elusive and a long list of studies shows little or no evidence
of increased flood magnitudes, with some studies finding
more evidence of decreases than increases.”
The paper said there was “no evidence that the areas
affected by the different types of drought are increasing”.
In conclusion, the findings do not mean we should do
nothing about climate change. “We should work to minimise
our impact on the planet and to minimise air and water
pollution,” the authors said.
“Whether or not we manage to drastically curtail our carbon
dioxide emissions in the coming decades, we need to reduce
our vulnerability to extreme weather and climate events.
“How the climate of the twenty-first century will play out is
a topic of deep uncertainty. We need to increase our
resiliency to whatever the future climate will present us.”