Climate Change and Variability, Transitions in the Phase of El Nino. Anthony R. Lupo, Professor Department of Soil, Environmental, and Atmospheric Science 302 ABNR Building University of Missouri Columbia, MO 65211

Introduction  Climate Change has become an important issue for society to confront. We can’t avoid it…  It is believed (in some quarters) much or all of the increase since the mid-19 th century is due solely to human activities.

Introduction  Global climate has been steady for the last 18 years, in spite of the continuous increase in atmospheric CO 2

Introduction  This has led to an increased interest in the (return to? ) concept of climate variability as a possible reason for the “hiatus”.  Climate has always changed ?

Climate: Definition  Climate  Is the long-term or time mean state of the earth-atmosphere system and the state variables along with higher order statistics. Also, we must describe extremes and recurrence frequencies.  Climate Change  is any change in the long term statistics.  Climate Variability  internal fluctuations that result from the interactions between parts of the climate system or within one subsection.

Climate The earth-atmosphere system, courtesy of Dr. Richard Rood. ( /lectures/)

El Niño  El Niño and Southern Oscillation / La Niña  El Niño has a periodicity of two to seven years. (Philander, 1989)  Defined as five straight months of the running six-month sea surface temperatures in the Pacific Ocean region < o C from the climatological mean.

El Niño  Maps / Data - August 2015

El Niño  El Niño history;  Noted in South America by the indigenous peoples of the region and “coined” El Niño by the Spanish in the 1660’s.  Sir Gilbert Walker and the Southern Oscillation in the 1920s

El Niño  J. Bjernes (1969) links SO to El Niño. El Niño of makes news! (Images “stolen” from PMEL – NOAA. 

El Niño  La Niña

El Niño  Impact on the USA is via the jet stream (El Niño: the 800 lb gorilla of short term variability)

Pacific Decadal Oscillationon  Pacific Decadal Oscillation  Only Known since the late 1990’a starting with Minobe (1997) and Gershunov and Barnett (1998).  PDO is a Pacific ocean basin-wide fluctuation (50 – 70 years) in SSTs.

Pacific Decadal Oscillation  Maps: PDO+ Warm east Pacific / Cold West Pacific  PDO+ PDO-

Pacific Decadal Oscillation  PDO+ from 1977 – 1998, and 1924 –  PDO- from , 1999 – present.   Modulates El Niño (Berger et al. 2003; Lupo and Johnston 2000; Lupo et al. 2002; Kelsey et al, 2007, Lupo et al. 2008; Birk et al. 2010).   May be linked to global themohaline circulation and North Atlantic Oscillation.

Missouri Impacts  The impact of El Niño on Missouri weather is very complex, but the impact of the PDO is to modulate the El Niño signal.  During PDO-, the El Niño signal is weak over most of the state, the only exception in southern Missouri. a)Columbia, MOTemperatures-PDO La Niña SeasonWarm MonthsCool MonthsNormal Months Winter11.8%3.9%84.3% Spring9.8%11.8%78.4% Summer5.9%17.6%76.5% Fall13.7%5.9%80.4%

Missouri Impacts  La Niña winters – generally cold for Missouri with more snow, and decent precipitation. Southern part warmer and drier.  El Niño – two types  Weak – Like La Niña  Strong – warm and dry winters with less snow, but southern Missouri is cooler and wetter with more snow.

Agricultural Impacts  El Niño thought to have no impact on summer weather.  New Research is showing that it is the transition between El Niño to La Niña that is correlated to summer weather, especially in Missouri. Newberry et al. (2016).

Agricultural Impacts  The transition toward La Niña generally is associated with hot dry weather in the summer (1954, 1988, 2011, 2012).  Transition to La Nina summers are 1-2 o F warmer than other summers. Also drier  The transition toward El Niño means generally favorable summer weather, cool and moist, but a dry spell late (2015).

Agricultural Impacts  Temperature – crop production 

Agricultural Impacts  Precipitation – crop production 

Extreme Weather  Extreme weather: Our research is showing no tendency toward more or less extreme monthly temperatures or precipitation in Missouri. (Hunch: PDO- associated with more extremes in MO)  But, the climate models project increased extremes?

Projection Short Term  Our Research group was successful in projecting hurricane activity and Missouri snowfalls from 2000 – 2015 based on PDO.  Our seasonal forecasts for winter and summer have been successful as well (see

Future Scenarios  Temperatures in the USA (National Assessment)

Future Scenarios  Precipitation in the USA (National Assessment)

Future Scenarios  How have the models been doing?

Our forecast – Winter  Above normal temperatures (around 1.0 sigma), possibly a good cold spell in February or March. Basically good news for heating bills.  Below normal amounts of precipitation, and less snow than typical. Maybe biggest snows in Nov and late.  Reasoning: We persist in a strong El Niño pattern. Strong El Niño periods are associated with warm and dry winters here with less snow. We’re fairly confident in this forecast.

Prediction Short Term  CPC Winter season – DJF (near normal temepratures and below normal precipitation and less snow? ‘Classic’ PDO+ El Niño signature )

Conclusions  Climate change is expected to influence this region over the next century, models are probably over-stating the strength of the changes.  Climate variability particularly the El Niño and Pacific Decadal Oscillation have a profound impact on our weather and climate in both winter and summer.

Conclusions  Climate variability is perhaps the larger issue for agricultural interests. Economically, adaptation is the best strategy for climate change whether it is human or naturally forced.  We have enough information now to project probable temperature and precipitation patterns for 4 – 12 months regularly and make reasonable generalized projections out one to two decades.

The End!  Questions?  Comments?  Criticisms? 