An energetic atmosphere and increasingly variable weather

07/07/16
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Many people are acutely aware that ‘something is up’ with the increasingly extreme weather events we are reading about and experiencing, but few take the time to examine the underlying fundamentals at work.  Science has shown that the earth’s atmosphere has warmed by about 1°C between 1880 and today.[1]  To many, this may not appear to be much of a problem.  After all, a human can barely register a 1°C shift in temperature.  The atmosphere, however, is a different story.

The earth’s atmosphere weighs about 5.5 quadrillion metric tons – a number so big it’s difficult to comprehend.[2]   The follow-up question is simple:  how much energy does it take to warm up 5.5 quadrillion tons of air by 1°C?   For our calculations, 1006 J/kg is a sound estimate.[3]  A Joule is a tiny amount of energy and it takes:

  • 1,006 Joules to warm up 1kg of air by 1°C;
  • 1,006,000 Joules to warm 1 metric ton of air by 1°C;
  • 1,006,000 J multiplied by 5.5 quadrillion (5,500,000,000,000,000) metric tons of air to warm up our atmosphere by 1°C.

Thus, it takes 5.533 x 10^21 Joules to raise the temperature of the earth’s atmosphere by 1°C. 

That is a lot of energy.  This energy has been added to our earth’s atmosphere, and the implications of this extra energy are significant for our global climate.  To understand why, you must look at the impact of energy on atmospheric conditions.

The earth’s atmosphere is a giant heat engine wherein the tropics are warm and the poles are frozen.  This atmosphere produces both hot and cold air masses, and when these masses meet they do work.  The implication of having added 5.533 x 10^21 Joules of energy to this heat engine is that there will be more work done.  The “work” of the earth’s atmosphere produces our weather, ranging from a light breeze to a tornado.  What we are witnessing in today’s variable global weather is the effect of this extra energy on the atmosphere, and its resulting work.  This takes the form of extreme and unseasonal events, such as tornadoes in December in Oklahoma, disrupted rainy seasons all over the tropics, and severe droughts coupled with too much rainfall all within a season in Brazil.

To provide some perspective, consider that hurricanes (inclusive of typhoon and cyclones), the largest atmospheric short-term ‘events’ on earth, release about 1.3x10^17 Joules per day in kinetic energy via wind, according to NOAA.[4]   If we estimate that our planet experiences an average of 35 hurricanes per year, each with a lifespan of 12 days, then it would take 101 years for all of the kinetic energy released by these storms to equal the amount of energy we have added to our atmosphere. 

To reiterate, there is a tremendous amount of additional energy in the atmosphere and it will do work.

What are the implications of this energetic atmosphere on agriculture?  In the agriculture sector, all weather outside of the norm is bad for business.  Consider a farmer in a semi-arid area who experiences an ideal sequence of rains and temperatures that should lead to a superior yield for their crops.  However, this ideal weather was outside the norm for the region, and as the farmer did not expect those weather conditions their selected crops, varieties and plant spacing were not suited to take full advantage of the exceptional weather conditions.  In this case, what nature provided in the form of ideal weather conditions wasn’t able to be leveraged to produce exceptional yields.  Other types of variable weather, such as too much heat, cold, precipitation or drought, will impose negative penalties on a crop.  Unfortunately for our farmers, these abnormal weather events are becoming the norm.

The negative impacts of weather events such as drought on agriculture are obvious, but there are also subtler implications.  Coffee trees, for example, suffer when nighttime temperatures rise, while humid conditions allow plant diseases to flourish.  Any conditions that are outside of the norm will leave farmers ill prepared and their crops at risk, as they try to battle the uncertainty of today’s climate.

All of these realities mean that we need localized agricultural weather data more than ever.  All across the agriculture value chain, businesses can use better data to alleviate the stresses of risky weather.  Input providers can use hourly temperature and humidity (forecast and observed) to predict when a disease might appear and if it would be economically impactful, and farmers can use forecast data in conjunction with observed data to determine many agronomic practices from top-dress fertilizer to irrigation planning.  Commodity traders can view abnormal weather patterns to inform their trades, and agribusinesses can use changing climate data to direct new varietal research.  Today’s agriculture needs to blend its traditional knowledge of the weather with ‘Big Data’ tools and analytics to better cope with the unknown of the increasingly variable weather.  Big data and information solutions are, and will become increasingly, a part of portfolio of practices all agricultural interests will employ to help alleviate these challenges.

[1] https://www2.ucar.edu/climate/faq/how-much-has-global-temperature-risen-last-100-years

[2] http://blogs.britannica.com/2012/01/how-much-does-earth-atmosphere-weigh/

[3] http://www.engineeringtoolbox.com/air-specific-heat-various-pressures-d_1535.html

[4] http://www.aoml.noaa.gov/hrd/tcfaq/D7.html Note that even more energy is released through condensation from hurricanes (5.2x10^19 Joules per day – more than 200x the amount of electricity produced on earth per day).

Topics: climate change, Food Security

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