Climate change and the drought

Source: Ames Tribune
Ames Tribune
Published August 6, 2012

The headlines scream: drought worse than the 1950s, worse than 1988, back to the dust bowl, food prices due for another spike, shortest corn carryover on record, water levels dropping, fish kills on the river, most over 100 degree days for a long time, and on and on.

Drought is insidious, relentless, gripping and depressing. Drought has influenced the progress of civilizations since the beginning of recorded history and before. The world’s first great civilization, established nearly 5000 years ago in Egypt, collapsed after decades of drought and Egypt plunged into a dark age that lasted for more than 1000 years. Ancient Israel once was the land of milk and honey. Other empires also collapsed around the world during this time.

One big driver of the world’s climate is the fluctuations in ocean temperature in the tropical eastern South Pacific off of Peru. This fluctuation is called the Southern Oscillation Index (SOI) and is becoming an important index in prediction of what is going on in world climate. This index is derived from the difference in sea level pressure anomalies (above or below average) measured at Tahiti and Darwin Australia.

When this number is positive, the water is warmer, and the condition is called El Nino, when negative and the water is colder it is called La Nina. Now if you are like me, remembering what these completely unrelated terms actually mean is hard, (I can never remember port and starboard either); just try to remember that El Nino is warm” and La Nino is cold. Some regard this warming and cooling as the normal way that oceans balance the ocean’s heat but it is now being greatly influenced by global warming.

Throughout history, the Pacific Ocean has oscillated back and forth between El Nino and La Nina, with a bit of quiet time in between. But this is not necessarily the case. Over the last 20 years, the warming phase has become dominate and longer lasting. In 1990-95, there were three El Nino periods with little break in between. This increase in warm periods may well be due to global warming. The El Nino is known to cause droughts in Australia and floods in South America. With El Nino, more water is evaporated, leading to high precipitation in some areas. When the ocean is cold (La Nina), the opposite occurs..

The shorthand for the trend is called ENSO, so when it is positive, we are heading toward warmer waters. That is the condition we are in now. However, direct prediction of the effects of positive ENSO has not been possible. This will take more refined models. To add to the challenge, there is a similar temperature pattern in the North Atlantic. Current indicators are that El Nino is again strengthening, very likely bringing our prolonged drought.

What seems to be clearer with time is that as the earth is warming as carbon dioxide increases, and this is definitely affecting the intensity and variability of the ENSO and increasing the rate and duration of the El Nino period.

Most of the papers I read on global warming now clearly recognize the dire effects. Even a recent Koch Brothers funded study concluded that virtually all of the temperature increase can be attributed to human emission of greenhouse gases. And Koch Brothers are the leading funder of climate disinformation in the world. In fact their study’s findings are even stronger than the Intergovernmental Panel on Climate Change. This report is really starting to change minds of the skeptics.

Yet there is no political will to slow or reverse the trend of increased greenhouse gas emissions. Rather, the mood seems to be that we can adapt to a new, warmer normal. This year may show that adaption is not a good strategy. How do you adapt when it is so dry and hot that annual crops do not provide economic yields. When water levels decline? When greatly increased populations over the next 4 decades will more than double the need for food even though the parched land will grow less and less?

If our politicians choose to ignore these questions just to win yet another term in office, shame on them. They do not display the leadership the world needs to climb out of the deep hole we have dug. Sorry grandkids, we are leaving you a mess.