On March 6, 2015, ICLR conducted a Friday Forum webinar entitled 'Rapid Arctic warming and extreme weather events in mid-latitudes: Are they connected? with Dr. Jennifer Francis of Rutgers University. Does it seem as though the weather gods have gone crazy lately? It is not your imagination. The question on everyone's minds is why, and is it related to climate change? In this fascinating presentation, Dr. Jennifer Francis of Rutgers University explained new research that links increasing extreme weather events with the rapidly warming and melting Arctic in recent decades. Evidence suggests that Arctic warming is causing weather patterns to become more persistent, which can lead to extremes such as droughts, cold spells, heat waves, and some flooding events. Jennifer Francis earned a B.S. in Meteorology from San Jose State University in 1988 and a PhD in Atmospheric Sciences from the University of Washington in 1994. As a professor at Rutgers University since 1994, she has taught courses in satellite remote sensing and climate-change issues, and also co-founded and co-directed the Rutgers Climate and Environmental Change Initiative. Presently she is a Research Professor with the Rutgers Institute of Marine and Coastal Sciences and studies Arctic climate change and Arctic-global climate linkages. She presently serves as a member of the Polar Research Board at the National Academies of Science, the Board for the Metcalf Institute at the University of Rhode Island School of Oceanography, and the advisory board for the UMass-Lowell Department of Environmental Earth, and Atmospheric Sciences.

1. Crazy Weather and Climate Change:
Are They Connected?
Jennifer Francis
Department of Marine and Coastal Sciences
Rutgers University
In collaboration with Steve Vavrus, U. of Wisconsin

2. Boston
One of the many snowstorms during winter 2015
The New Yorker

4. U.K. Winters 2014, 2015
Japan 2012
Extreme weather events are on the rise…
from Munich RE

5. So, what the heck is going on??
Is human-caused climate change
playing a role?
YES!

6. Present
CO2 levels
are WAY out
of whack
with
temperature
CO2 now highest in at least
the past 800,000 years
NAS, Oct. 2012
We’ve put ourselves in a real pickle…
The last time CO2 levels were this high, the globe was
several degrees warmer, sea levels were tens of feet higher.

7. But warming is not even
around the globe.
Jan. 2015 was 359th
consecutive month
warmer than 20th
century average
CO2 levels are highest in
at least 800,000 years,
and Earth’s temperature
is responding…
…the warmest 19 years
occurred in the past 20
years.
From NASA/GISS
Surface Temp. Anom.
2005 to 2014

8. How do we know that humans
are responsible?

9. Evidence implicating
humans
One of our best tools:
computer programs
- climate models -
that simulate the
complex physics of
the atmosphere,
ocean, snow, ice, and
land and all the
forces acting on
them.
Solar + volcanic
(natural)Observed
Modeled
All forcings
(natural + human)

10. And the atmosphere is gaining moisture…
…providing more fuel
to energize storms, a
stronger greenhouse
effect…
…and an increased
frequency of heavy
precipitation events.
from ClimateWatch.noaa.gov
Global specific humidity

11. Sea ice is now a mere shadow of former self…
About HALF of summer ice cover has been lost…… in only 30 yearsWhat’s left is “rotten” and “slushy”…and 75% of the ice volume…

12. 2012
How unusual is the recent loss of Arctic sea ice?
NOAA Ice Age Animation

13. Ice extent September 2012
Mean ice extent
1979-2000
The Arctic is
warming 2-3
times faster
than the rest
of the globe

14. Arctic
Mid-
latitudes
Near-surface air temperature (Fall)
“Arctic Amplification”

15. Arctic Amplification
Not confined to surface!
250 hPa
surface
Temperature changes
1995 to 2013
40oN 80oN
Height changes
1995 to 2013
40oN 80oN

16. COLD
WARM
Consider a layer of atmosphere stretching from here (warm)
to the Arctic (cold)
Because warm air expands, the layer will be thicker here
than it is in the Arctic.
Air flows down this “hill”, turns
to the right as the Earth spins,
and creates the Jet Stream
As the Arctic
warms faster, the
hill flattens, and
the jet stream
weakens

17. OND
~10%
Northern hemisphere mean U500
Zonal
wind
Sea ice
area
West
Winds are
Weakening…
“Weaker
Westerly
Wind is
Wavier”

18. When the waves are
small, they move
eastward quickly.
When the waves are
large, they shift
eastward more slowly. Graphics by John Garrett for SkepticalScience.com

19. OND
Why do we care about these waves?
The Jet Stream makes our weather
Wet and
stormy
Dry and
settled
NASA Jet Stream

20. Chain of Events Linking Arctic Amplification (AA) with
Increased Extreme Weather in Mid-Latitudes: a hypothesis
Arctic
Amplification
Poleward
temperature
gradient weakening
Upper-level flow
becoming more
meridional
Upper-level
westerly winds
decreasing
Amplified patterns
more frequent
Larger waves
progress eastward
more slowlyMore persistent
weather patterns,
extremes more
likely
Francis and Vavrus, 2012
The mechanisms
are emerging…

21. Is the jet stream
becoming wavier?

22. A “topographic map” of a layer
in the atmosphere

23. Jan 6 2014 “Polar Vortex”
Amplified patterns
more frequent5 High-Amplitude Patterns (HAPs)
500 hPa contour range > 35o
latitude
Unprecedented Spain flooding

24. Are very wavy jet-stream patterns
really happening more often?
Fall (Oct-Dec) Northern Hemisphere
Upper-level westerly winds
High-amplitude wavesHigh-amplitude waves
Upper-level westerly winds
Fall (Oct-Dec) North Atlantic

25. Change (%) in frequency of high-amplitude patterns
1995-2013 versus 1979-1994
Region JFM AMJ JAS OND
Atlantic
285 – 60E
19* 5 57** 47**
North America
220 – 290E
18* 12 59** 23
Europe
-15 – 45E
1 3 6 17
Asia
30 – 150E
4 1 -15* 65**
Pacific
150 – 240E
-18 12* -3 25*
Northern
Hemisphere
-6 1 -5 16
< -40% -39 to 30% -29 to 20% -19 to 10% -9 to 0%
0 to 9% 10 to 19% 20 to 29% 30 to 39% > 40%
* > 1 SD, ** > 2 SDFrancis and Vavrus, 2015

26. Do recent extreme weather events
patterns fit this story?
Boston – early February 2015

27. March 2012 Feb. 1-14 2015
Accuweather
Surface Temp. differences from normal

28. “Ridiculously Resistent Ridge/Trough:” Dec.‘13-Feb.‘14
Warm
Warm
Cold

29. “Ridiculously Resistant Ridge/Trough”
19 Feb. 2015
Déjà
vu?

30. Ridiculously Resilient Ridge/Trough Pattern Evident in
2014 Average Temperature Departures

31. Did Climate Change Contribute to Sandy?
YES! – In At Least 5 Ways
Was block strengthened,
extended northward, or
prolonged by warm Arctic?
We think so.
J.A. Francis
✓Sea level rise
✓Warmer oceans
✓Warmer air
✓More water vapor
➢Arctic sea ice loss?
The Arctic was MUCH warmer than normal
Blocking High

32. Summary
West winds
weakening
?
Arctic warming

33. THANK-YOU !!francis@imcs.rutgers.edu

34. Extras

35. THANK-YOU !!francis@imcs.rutgers.edu

36. January 2015 is
warmest January
on record.
Jan. 2015 zonal
temperature
anomalies
Arctic
Equator