Editorial: In a word, why climate change matters: Water

Why should Chicagoans care if parts of the globe run out of water? Because water crises can lead to large-scale migration, and even conflict.

Think climate change and what comes to mind? The Arctic Ocean melting like an ice cube under a July sun? Island paradises swallowed up by rising seas? Beefier hurricanes crashing into coastlines with greater frequency?

There's a ring of truth to all of the above, and it should make all of us think and act greener. Now, the World Bank has come out with a report that sums up one of the gravest of climate change consequences with just one word: water. As in, not enough of it.

By 2050, the report projects, water scarcity could cause economic growth in some parts of the world to drop by as much as 6 percent. Regions where water is plentiful will get thirsty, and regions already struggling with scarcity will get thirstier. Water availability in cities could plummet by as much as two-thirds by 2050 compared to 2015 levels.

The World Bank makes a good case for the linkage between global warming and water scarcity. Steady population growth in coming decades will produce a bigger demand for water. The world's population is expected to top 9 billion by 2050. That means food production will need to double, and ramping up agricultural output requires setting aside more water for farming. More people also means a need for more energy. Providing power is one of the biggest consumers of water. By 2035, the World Bank predicts, energy is expected to consume 85 percent more water than it does now.

At the same time, global warming will push up temperatures, creating more evaporation — meaning there will be less water at a time when farms and power producers need more of it. And with global warming come rising sea levels, which destroy coastal aquifers with salinity, further reducing available fresh water.

It's not that global warming  sops up water and never returns it. Rather, water is being redistributed in ways that make matters worse for water-scarce regions. Those regions, for the most part, include poorer, developing countries that lack the wherewithal to solve water scarcity. Parts of the world most at risk include the Middle East, North Africa, Central Asia and Central America. Overall, a quarter of mankind lives in places burdened by water scarcity, the report states. In 20 years, that share could double.

It all sounds fairly grim. The World Bank, however, offers up some solutions. Too many cities and towns around the world make water free. The report advocates pricing that reflects water's value. We're likely to be better stewards of water if we price it as the precious commodity it is.

Desalination plants that turn seawater into drinking water have been godsends to countries such as Israel that for decades coped with water scarcity, but that approach has a flip side: Desalination devours energy and is therefore expensive. The report also touts recycling storm water and "gray water" — water from sinks, showers, tubs and washing machines.

Those remedies help, but they work around the edges of the core problem — climate change.

Reducing greenhouse gas emissions should top the list of answers. The Paris agreement on climate change, signed by more than 170 nations in April, is a good start. That accord calls for reductions in greenhouse gas emissions that would limit the planet's warming to an increase of no more than 3.6 degrees above pre-Industrial Revolution levels.

Countries still need to hammer out action plans to meet that goal, however, and then act on those plans. The World Bank, the International Monetary Fund and many world leaders believe the right incentive to coax emissions reductions is to impose "carbon pricing," requiring fossil fuel polluters to pay for carbon dioxide they send into the air. President Barack Obama backs the concept, but he's leaving office in January.

Chicago is perched  on one of the world's most plentiful fresh drinking water sources — one of the Great Lakes. So, why should Chicagoans care if parts of the globe run out of water? Well, water crises can lead to large-scale migration, and even conflict. The report is careful to not suggest that water scarcity will start wars between nations, but it does stress that water scarcity has in the past sparked violence and civil conflict within countries. "In a globalized and connected world, such problems are impossible to quarantine," the World Bank says.

The report ought to be a wake-up call to a world that has treated water as if its quantity is boundless. It's not. It's finite and increasingly scarce, and we need to start learning how to manage it better. One of the best ways to do that is to confront climate change head-on.

Lake Michigan Water Levels Video 

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• Climate Change
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1 Comment

1. Confronting climate change head on to improve water management is a cop-out.
   The best way to manage water better is to manage water better.
   Pricing water for agriculture could reduce waste dramatically. In Indonesia, a ten per cent reduction in water use for agriculture would be roughly equivalent to present total domestic and industrial water use.
   Some estimates place water losses and waste in irrigation as high as 50%. Such waste of water has been attributed to high subsidies for water use in agriculture. Where infrastructure for irrigation systems are also subsidized, the effective subsidy for water use probably reaches several hundred per cent.
   Mismanagement of water caused the degradation of the Aral Sea, not climate change.
   Geologists in Kansas project by 2065 or so the Ogallala Aquifer will be 70% depleted. Depletion of fossil water is caused also by poor management whether in Kansas or the Sultanate of Oman. The only thing that has saved the Issyk Kul (Kirgyzstan) is its salinity, low as it is.
   Reducing water use for paddy rice has been shown to save water, increase yields, and reduce methane generation. (I believe the IRRI has confirmed this by experiment.)
   In Egypt and elsewhere, watter-logging in parts of fields results because fields are not level. Excess water is used because of field configuration.
   Some countries and regions claim climate change is the cause of water stress for crops and periodic drought. Look more closely at centennial scale data for Australia and California and you will discover long histories of periodic drought. More recently we have learned that severe ENSO events are associated with water stress. Yet these are precisely the regions that export most of their water in the form of crops. (Severe ENSO events are not considered to be related to climate change, though still discussed in the literature.)
   Finally, the paper by Belda et Al (2014) is probably the best to date in reconstructing the global Koppen-Trewartha climate classification map. The maps show the climate regions of the world (except Antarctica) for two periods, 1901-1931 and 1975-2005, based on a 30 minute grid, average area about 2500 km2, (About 50,000 grid cells cover 135 million km2, the land area of the Earth except Antarctica.)
   Between the two periods separated by 75 years, 8% of the cells changed climate type. When you plot a scatter diagram of distributions for the two periods, you will find there is little divergence from the straight line passing through the origin and with slope unity. R-squared is 99.5.
   The paper does not discuss error bars. However the data used has since been revised to remove wet bias, an adjustment that would increase R-squared, indicating even less change in climate-related ecological conditions than these maps show. (Global estimates of precipitation increase during the last 150 years have recently been revised downwards.)
   In any other field of Earth science, using data with similar precision, we would claim confirmation of the null hypothesis that the two data sets separated by 75 years are not significantly different.
   So yes, climate has changed a little, but most people worldwide are better off than their parents and grandparents. The people benefiting the most are those on the margins of steppe to desert and those on the margins between ice and tundra where warming and additional rainfall have had the most positive economic effects. Tropical areas show little change.
   Most studies of water deficit in relation to needs do not take into account the huge expansion in need for water that has been generated by the more than doubling of population since 1950 and the associated land-use changes both urban and rural, including the expansion of land under irrigation.
   Without urbanization, made possible by plentiful cheap energy, global water needs would be dramatically greater than what they now. We should therefore be cautious in what we aim for in respect to climate and the means to achieve it.
   To focus on the effects of global warming of a degree Celsius since the depths of the Little Ice Age misses the point entirely. Maps prepared using satellite data to depict the NDVI have shown decades of greening that has been attributed to reduced need of plants for water resulting from reduced evapotranspiration, a physiological response of plants to increased CO2.
   By all means, let us aim for better water management. But the main challenges are political and financial, specifically over-subsidization of water, which encourages mismanagement, both by bureaucrats supported by development banks and development cooperation agencies, and wasted by water users mainly in irrigation. The adverse consequences are economic and social.
   Reference:Climate classification revisited from Köppen to Trewartha, Belda, M. et al, Climate Research, 2014http://www.int-res.com/articles/cr_oa/c059p001.pdf
   NDVIhttp://visibleearth.nasa.gov/view.php?id=1804
   http://www.co2science.org/subject/g/summaries/greeningearth.php