Water-Food-Climate Squeeze: Can we bio-engineer our way out?

Dr. Praveen Kumar, Professor of Civil and Environmental Engineering at the University of Illinois at Urbana-Champaign, gave a talk titled The Water-Food-Climate Squeeze: Can we bio-engineer our way out? He discussed the topic from an physical, biological, and climatological prospective. He focused on a few fundamental problems such as how will we feed people as our global population grows? Also, what changes will occur to plants and crops do under climate change.

We need to increase crop yield, improve water use efficiency, increase albedo (reflectivity), and use the same amount of land for crops. Interestingly Kumar showed that arable land is increasing in developing countries but declining in developed countries, but the ultimate takeaway is that cropland per person is decreasing fast. Fifteen percent of terrestrial land is devoted to agriculture. With water, the more we use in agriculture means there will be less for consumption.

The University of Illinois has conducted a field study growing soy and corn crops at elevated carbon dioxide levels, focusing the talk on the 550 ppm level, a likely concentration in the future. They found that the plants had a clear increase in their temperature and decrease in transpiration, as well as changing the chemistry.

Dr. Kumar then ran a model to try and understand what is causing these changes. It found that plant productivity is heterogeneously distributed vertically, and we may be able to take advantage of this to optimize production. It may be possible to find vertical structures for a whole canopy that will allow increased productivity, reduce water use, increase albedo, and increase photosynthesis, simultaneously. When searching for a solution that could maximize or minimize the key factors, it was found that optimal leaf area index was less than existing, meaning that if we decreased the number of leaves then it would increase the yield. Without making changes to the genetics of the crops this result can have impacts on the amount of food produced.

The results are robust under present and climate change scenarios. The science behind Dr. Kumar's research, as well as many other scientists, is going to help agriculture continue to improve with or without a changing climate. The future of the science is to look at very fine resolutions, on the meter scale via remote sensing techniques such as LiDAR (Light Detection and Ranging), to find the best ways to spatially grow crops with the natural topography. The small-scale depressions and subtleties in topography will have impacts on the hydrology and thus growth of crops differently. To optimize the water use and land use, there will likely be assorted crops planted in a single field based off the topography.

Ten-year anniversary: Was Hurricane Katrina "caused" by global warming?

In the aftermath of Hurricane Katrina, ten years ago, the question emerged of whether global warming "caused" this event. Climate Central recently looked back on this question and what we have learned.

The process of determining what caused an extreme climate event is known as attribution, and its a tricky game. The first step is to ask the right question. Increasingly, climate science is recognizing that based on what we know about climate change, the question of whether an event was "caused by" climate change is not answerable.

Why? The atmosphere is warmer and wetter now, due to human-caused global warming. It is more energetic and more able to extract moisture from soils, plants, and open waters. Similarly, ocean surface temperatures are warmer, providing more energy to the overlying atmosphere. How could a weather event develop in such a context and NOT be influenced by these changes? A more appropriate question might be "How much did global warming contribute to this event?". Increasingly, this is where attribution studies are heading. 

What have we learned regarding Katrina? A few highlights:

• Warmer ocean intensified storm by adding vapor and energy
• Higher sea level increased the storm surge by 15-60%
• Subsidence of the land adds to damage from storm surge
• Land lowered by pumping of groundwater and oil
• More generally, studies suggest that in a warmer world
• Hurricane intensity will increase
• Numbers of hurricanes may be stable (?)
• Tracks will shift northwards
• Odds of truly major events (e.g. 1/10,000) will increase

Strong El Niño predicted for 2015-2016

Strong El Niño predicted for 2015-2016

Several US and national climate research groups are predicting an unusually strong El Niño event to occur this year, based on current very warm conditions in the tropical Pacific (above, SST anomalies) and associated conditions across and deep in the Pacific ocean. In fact, this year's event may equal or surpass the strongest events on record that occurred in 1982-3 and 1997-8. Today's lecture covers more about what that means for global climate. This prediction has led to many catchy names - Godzilla, Bruce Lee (huh??) - but the event is no joke. It has the potential to ameliorate drought across the Southwest and has already been implicated in the unprecedented observation of three category-4 cyclones at one time in the tropical north Pacific. The El Niño event also puts us firmly on track to have the warmest year on record this year (again...). 

The figure below compares this year's warming to 1997 (on the left) and shows the forecasted winter precipitation on the upper right. Break out the skis!

How volcanic eruptions influence the arts

In this week's Science Times (New York Times), William Broad describes how a powerful volcano in 1815 influenced not just climate, but also painting and literature. In April of 1815, the volcanic peak Tambora, on the island of Sumbawa in present-day Indonesia, lost a mile of elevation in a powerful explosion that was heard for hundreds of miles around. The dust that was injected into the atmosphere reflected radiation, cooled climate, and led to the "year without a summer" across much of the northern hemisphere. Blizzards in June, hail throughout the summer, and very little sun led to crop failure and famine. 

The particles in the atmosphere led to spectacular skies and red sunsets, depicted in many paintings from that era. In fact, studies of paintings done between 1500-2000 have documented an increase in the amount of redness of the skies that corresponds with known volcanic eruptions (paper here). The 19th century was a time of frequent volcanism, and several paintings show this influence. A famous example is Edvard Mönch's "The Scream," shown at left. 

As well, the gloomy summer led to literature of lasting importance. According to Broad, 

"That June [1816], the cold and stormy weather sent the English tourists inside a lakeside villa to warm themselves by a fire and exchange ghost stories. Mary Shelley, then 18, was part of a literary coterie that included Percy Shelley, her future husband, as well as Lord Byron. Wine flowed, as did laudanum, a form of opium. Candles flickered.

In this moody atmosphere, Mary Shelley came up with her lurid tale of Frankenstein, which she published two years later. And Lord Byron hit on the outline of the modern vampire tale, published later by a compatriot as “The Vampyre.” The freakish weather also inspired Byron’s apocalyptic poem “Darkness.”  "

Global warming makes drought worse

"California Drought Is Made Worse by Global Warming, Scientists Say"

A recent NY Times piece (Justin Gillis, 8/20/15) picked up on a new study showing how the California drought is being intensified by rising temperatures. The study, led by Park Williams of Columbia, calculated that the drought was about 15-20% more intense than it would have been under slightly cooler (natural) conditions. Why is this? We'll discuss it in class and post the answer later!

The original paper is here (free access from UA campus, otherwise behind paywall).

Photo from the NYT story.