The long range weather forecast is always a riddle. There is no such thing as “average weather”. That’s a statistical (cover your butt) term that has no resemblance to reality. Here in Minnesota and the Upper Midwest we ricochet from one extreme to the next. And those extremes appear to be getting more extreme over time.
Short term we’re heading from an “ENSO-neutral” scenario in the Pacific Ocean (temperatures close to long-term averages) to a developing El Nino warming phase by the summer of 2014, according to NOAA’s latest predictions. El Nino events tend to energize the southern branch of the jet stream, even during the summer months, and this often results in a cooler, wetter bias for much of the USA. Stronger winds over the tropics resulting from El Nino can shred developing tropical systems. Strong El Ninos are often accompanied by fewer tropical storms and hurricanes. It’s too early for specifics, but we may be looking at a moderate El Nino, reducing (slightly) the threat of drought, but potentially increasing the number of severe storms from late spring into summer.
Brewing El Nino
For a few months now we’ve been tracking warm water in the Pacific spreading east, toward the Americas. According to NOAA there is now a statistically significant chance, higher than 50-50, that a moderate El Nino will develop by late spring or early summer, and linger for much of 2014. What happens in the oceans, especially the Pacific, tends to have a domino effect on weather patterns downwind, and I expect El Nino to have an influence on our weather patterns into the fall and winter months.
June – August: Slight Cool, Wet Bias?
Based on historical El Nino warming of the Pacific Ocean Minnesota and much of the Upper Midwest can expect a (very) slight bias toward slightly cooler summer temperatures, with above-average precipitation, due to a more active southerly branch of the jet stream. Graphic source: NOAA Climate Prediction Center.
Any El Nino impacts will be superimposed upon larger trends we’re witnessing, specifically an apparent increase in the frequency and intensity of weather events, worldwide. An increase in temperature means the atmosphere can hold more water vapor, more fuel for floods, more potential energy and moisture for everything from hurricanes to coastal storms and blizzards. Data from reinsurance company Munich Re shows the trends:
Natural Cycle or Trend?
Data since 1980 shows an increase in extremes ranging from severe droughts and wildfires to flooding events and extreme heat, worldwide. This spike coincides with CO2 (carbon dioxide) levels reaching 400 ppm (parts per million), the highest reading in 800,000 years. Scientists are most concerned about the rate at which we’re dumping CO2, methane and other greenhouse gases into the atmosphere, a 30% increase since pre-industrial times. Volcanic eruptions hundreds of millions of years ago may have pumped more CO2 skyward, but this occurred over many millions of years. It’s the rate of increase that has many experts alarmed.
How much of the increase in extremes is natural variability vs. possible symptoms of a warmer, wetter atmosphere and resulting changes in jet stream patterns? Have we reached the point where we can we pin any one storm or specific weather event on climate change? Are we inadvertently loading the dice in favor of more weather extremes in the years ahead?
I’m all for coincidence and serendipity, but at some point denying the trends are just plain stupid. 13 of the 14 warmest years, worldwide, have occurred since 2000, according to NASA and NOAA. Anyone under the age of 29 has never lived through a cooler than average month, worldwide. The 20th century was the warmest in 1,000 years. We’ve gone from scientific theory to meteorological reality. Here are some of the very trends we’re already witnessing, courtesy of Climate Nexus:
- Wildfires in the U.S. are getting larger, and researchers attribute this to warmer temperatures. From 2002-2011, fires cost the U.S. an average of $1.2 billion per year.
- According to the 2013 IPCC Fifth Assessment Report, North Atlantic hurricanes have grown more intense, and this is projected to continue due to climate change. Precipitation associated with hurricanes is also projected to increase.
- Global sea levels have risen, meaning that even average-sized storms are causing more damage due to storm surges. One study found that due to sea level rise, 80,000 more homes were exposed to flooding during Hurricane Sandy.
- Heat waves are intensifying and becoming more widespread.
- Precipitation is being concentrated into more extreme events. This contributes to flood damages, and costly events like the 2013 extreme Colorado floods are in line with this trend.
Drought causes high damage costs to farms and businesses, and past droughts have been found to be worsened by climate change (including the 2011 Texas drought costing $7.62 billion). Dry areas are projected to continue to get drier, according to the IPCC.
Arctic sea ice continues to melt off rapidly during the summer months; a new record low for ice was set in 2012, and 2014 will probably see a record or near-record melt of polar ice, and the ice cap over Greenland remains unstable. Computer models have not done a reliable job estimating ice melt, if anything underestimating the rate of melting in recent years. There’s a growing body of evidence that changes at the Top of the World may be having a ripple effect, impacting the speed and configuration of jet stream winds at our latitude. Research out of Rutgers suggests a 12% drop in jet stream winds in recent years, resulting in more amplification, more “waves”, dips and bulges in the steering winds, which can cause weather to move slower, literally getting stuck for days or weeks at a time. When this happens floods can be more severe, as can heat waves and the severity of droughts. This is what I’ve been witnessing on my weather maps, especially since 2010.
A Statistically Unlikely Event
Hurricane Sandy should have swept out into the Atlantic in late October of 2012, swept along by prevailing westerlies in the jet stream. But record ice melt over Greenland the previous summer created an unusual bubble of warm high pressure over the North Atlantic, which steered Sandy into coastal New Jersey. We’re seeing more unusual contortions of the jet stream, more huge north and south swings with prevailing winds stalling for extended periods of times. Although more research and data is required, this may be an early symptom of record ice melt in the Arctic and Greenland. The “Polar Vortex” all but stalling out over eastern Canada and the eastern USA this past winter may be another symptom of new instabilities in the jet stream. But the impacts of climate volatility are showing up even closer to home:
Thousand Year Floods
The Minnesota Climate Office reports a total of 4 separate 1 in 1,000 Year Floods in Minnesota since 2004, including the June, 2012 North Woods Flood that swamped the Duluth area with historically significant amounts of rain, as much as 8-12”. Think about that: four floods that should, at least theoretically, occur every 1,000 years, have struck Minnesota in just the last 10 years, statewide. Flash flooding is increasing across the Upper Midwest, Great Lakes and New England, where meteorologists are tracking the greatest uptick in extreme summer rains.
For the record, it wasn’t an Al Gore documentary that got me off the dime, talking about the trends and attempting to connect the dots. It wasn’t even peer-reviewed scientific papers that initially got my attention. After witnessing shifts in patterns that fell well outside the realm of “normal weather”, after pouring over weather data, attempting to connect the dots, and then finally diving into the research, it dawned on me that we were witnessing a new level of weather volatility. A warmer, wetter, more energized climate system was impacting jet stream winds and flavoring all weather, which, increasingly was becoming “stuck”. And when weather stalls bad things happen: record floods, sudden droughts, more weather-whiplash; going from one extreme to the next.
Acknowledging a changing climate doesn’t rest on one slender thread of evidence. From shrinking summer ice at the top of the world impacting jet stream winds and weather extremes to shrinking glaciers, more acidic oceans, an uptick in severe heat waves and devastating droughts and summer downpours symptoms of a warmer, more volatile climate system are everywhere you turn. And they are showing up in the skies above Minnesota.
In my presentation on May 13 I’ll review the evolution of my personal experiences with weather and climate, going from skeptic in the 1980s and early 1990s to acknowledging the data and trends, and realizing, over time, that climate theory had become a meteorological reality. What are the trends and how can we make our cities, farmland and infrastructure more resilient, able to better withstand these larger swings in temperature and moisture, what I dub “climate volatility”? Going beyond the gloom and doom of the “Apocalyptics” while addressing climate denial directly – how can a rapidly changing climate result in a steady stream of innovation and reinvention, creating the new technologies that will not only help us power the economy with less carbon, but leave America more competitive and energy-independent in the process? And how much evidence is enough? Is there a critical mass of data that is robust, reliable and actionable? These are some of the topics I hope to address during my Secure360 talk in early May.