Worldwide Droughts Linked to Surface Ice Melt
by Jenny Griffin, Environmental Writer, South Africa
August 9, 2012
As atmospheric temperatures continue to climb, ice sheets are melting across the Arctic circle on a scale higher than we have ever witnessed. This not only causes sea levels to rise, but also causes other impacts that pose a more serious risk to humanity. Warming atmospheric temperatures can cause a chain reaction affecting other natural processes on a global scale, including ocean processes, weather patterns and regional climate. The impact of severe weather events, such as drought, floods, and storms will become more intense as global temperatures steadily increase.
Unprecedented Surface Ice Melt
July 2012 saw unprecedented surface ice sheet melt in Greenland; with 97% of surface ice sheet having thawed. This is the largest recorded thaw since satellites began monitoring these events more than thirty years ago. Data from ice core samples show that a thaw of this magnitude last occurred in Greenland in 1889. What is alarming is that satellite images show that on July 8, 2012, 40% of Greenland's surface ice sheet had melted, but by July 12, 2012, this had rapidly escalated to 97% – amounting to a 60% thaw in a mere three day window period.
According to NASA's satellite image data recordings, this rapid thaw was triggered by unusually high surface temperatures that coincided with this event. Greenland has experienced a series of heat waves since the end of May, with the latest ridge of hot air moving over Greenland on July 8, 2012, and settling over the ice sheet by July 12, 2012. It started to dissipate a few days later, but by then much of the surface ice had already melted.
In recent years it is not unusual for half of Greenland's surface ices sheets to experience some degree of summer surface melt. But this year's massive meltdown, which occurred over such a short period, is considered an unusual event, and is getting climatologists to sit up and take notice. While data from ice core samples indicate that events of this magnitude seem to occur naturally every 150 years or so, implying that this could be a part of a natural cycle, global warming is significantly more of an issue now than it was 150 years ago, so there is good reason to be concerned over this event. Firstly, much of water lost from the melting ice sheets flows into the ocean, where it causes sea levels to rise, posing an increasing threat to coastal communities and island nations. But more importantly, ice provides an albedo affect, reflecting heat away from the earth, and thus plays an important part in reducing the effects of global warming. As the ice sheets melt, this effect is diminished, because sea water, which is dark in comparison, does the opposite – it absorbs and retains heat, rather than reflects it away. This is a feedback effect, which further increases the rate of global warming.
Rising temperatures cause more moisture to be evaporated from both the land and the surface of the oceans, resulting in higher levels of moisture in the atmosphere, while land surfaces and soils become drier. Water vapor also traps heat, and as such, is considered a greenhouse gas too. This provides yet another feedback effect that increases the rate of global warming. Higher atmospheric moisture results in increased precipitation; however, rainfall it is not dispersed evenly throughout the world. This is primarily due to shifts in atmospheric and oceanic circulation patterns, brought about by warming atmospheric temperatures, which further disrupts weather patterns throughout the world. So while one area in the world may experience heavy rainfall and flooding, other areas will experience droughts.
Much of the northern hemisphere is currently experiencing extreme drought conditions, with many of the affected areas being major food producing regions. Prime crop growing regions in the USA, Russia, China, Europe, and North Africa are experiencing some level of drought, with much of the affected area experiencing extreme to exceptional drought. Currently more than 754 million people are living under exceptional drought conditions. In the US, more than 60% of the nation is experiencing some level of drought, varying from mild/moderate to extreme/exceptional. According to USDA, July temperatures averaged 4-8° higher than normal, with some areas witnessing the highest temperatures on record. Rainfall was less than 50% of the average rainfall expected for July in many areas.
Droughts are threatening food security across the world, putting many nations at risk of food shortages, which could threaten lives. Areas where the risk is less will still be affected by escalating food prices, due to the worldwide shortages of basic food products, such as wheat, corn, and soya beans.
The USDA estimates that around 88% of the US corn and soya bean crop are currently under some level of drought, while hay in drought is around 65%, and cattle under drought as much as 72%. Shortages of corn, for example, do not only mean that food products made from this commodity will be in short supply; there are other ramifications to this. Fodder is also in short supply due to failed crops, forcing many farmers to sell off their livestock due to poor grazing, and rising price of animal feed. When the price of animal feed rises to a point where farmers are not likely to make a profit when they sell their livestock, they start culling their animals. The market may initially be flooded with meat products as a direct consequence of this, resulting in a short term price drop, but in the coming months, meat products will become scarce, resulting in the price escalating to reflect this. It is likely to affect other areas of the economy as well. Farmers may be forced to cut back on staff, and meat packing plants may be forced to cut down shifts, or even lay off staff, if the situation worsens.
Poorer nations are always the hardest hit by food shortages, and rising food prices. People living in these nations very often have little or no income, surviving on subsistence farming, or growing cash crops to sell or barter in local markets. North Africa has been plagued by droughts for centuries, and countless lives have already been lost due to starvation, malnutrition, and diseases associated with poor water quality. People living in this region face unbearable hardship from famine and drought. Many people have no access to safe drinking water, and with escalating droughts, they have no water to irrigate their crops or to keep their livestock alive. Food imports are costly, and are likely to become even more so as food shortages are experienced worldwide. Relief aid very often does not reach the most vulnerable people scattered in remote areas further away from centralized ports, towns and villages.
As the world gets hotter, worldwide droughts are going to become more common and more regular. The scenario in Africa could realistically spread to other countries as droughts intensify around the world. The only way that we can prevent this from happening is to make concerted efforts to prevent temperatures from increasing any further. The only way that we can do that is by reducing greenhouse gas emissions.
According to NASA climatologist Bill Patzert, "CO2 is up from 280 parts per million in the 19th century atmosphere to 400 parts per million now -- a 43% increase. We're emitting six times more carbon from fossil fuel use now than we did 50 years ago. Atmospheric CO2 hasn't been this high in 400,000 years." Carbon dioxide and other greenhouse gases trap heat, causing atmospheric temperatures to steadily rise. This trapped heat is radiated back to Earth where it is absorbed and stored in the oceans. The increase in atmospheric and oceanic temperatures is not only causing ice sheets to melt, and sea levels to rise, it is also causing worldwide droughts. This is feeding back into a system of warming that is rapidly becoming self-sustaining, and in real danger of reaching runaway proportions that we will not be able to stop.
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9 Nov 2015 World Bank article Climate Change Could Put 100 Million People Back Into Poverty by Destroying Farming. 900 million more could sink into poverty
IPCC 5th assessment 2014 Based on many studies covering a wide range of regions and crops, negative impacts of climate change on crop yields have been more common than positive impacts (high confidence) WG2 SPM.
Without (successful) adaptation, local (/global is the same for 1.0C) temperature increases in excess of about 1°C above pre-industrial is projected to have negative effects on yields for the major crops (wheat, rice and maize) in both tropical and temperate regions(IPCC AR5 WG2 Ch7 Exec Summary p.3 final science draft).
With or without adaptation, negative impacts on average yields become likely from the 2030s with median yield impacts of 0 to –2% per decade projected for the rest of the century, and after 2050 the risk of more severe impacts increases. IPCC AR5 WG2 Table 7-3.
September 2014 Scientists on drought: Scientists warn of 'megadroughts'
Nature Mar 2014 Climate change will reduce crop yields sooner than we thought.
National Geographic 20 Feb 2014
British Floods, California Drought: A Connection?
A wavy jet stream—and perhaps climate change—underlie recent weather extremes.
Most are becoming aware that the world is being hit by severely damaging increased extreme weather events. In particular these since 2000 have affected the world's best food producing regions of the Northern Hemisphere (NH).
The evidence amounts to causation since the publication of Potsdam Climate institute 2013 paper amplification of planetary waves and recent Northern Hemisphere weather extremes '... amplification of planetary waves and recent Northern Hemisphere weather extremes' on the NH climate dynamics at work.
We are already committed due systemic inertias to a global warming above 2.5C and on our current world economy at mid century.
Increasing world drought (especially N. hemisphere) has resulted in a global water crisis that is causing world grain reserves to fall and global food prices to become volatile. This in turn is causing a committed increasing global food crisis that is a global emergency (Center for Climate & Security Jan 2013)
Evidence suggests world drought has been increasing driven by global temperature increase as expected. Since 2000 the record shows an extraordinary increases in Northern hemisphere heat and drought. Today (Dec 2012) central US (great grain belt) in a three increasing year drought predicted to persist the April 2013.
In particular over the past decade, and 2012 especially, all the world's top food producing regions in the North hemisphere are being hit by drought.
21 August 2012 – "More consolidated efforts to combat the threat of climate change and counter its ripple effects on global food security are needed amid an intensifying global drought and increasing temperatures worldwide," the United Nations declared today.
With drought intensifying worldwide, UN calls for integrated climate policies.
"Climate change is projected to increase the frequency, intensity, and duration of droughts.
One quarter of the United States was experiencing exceptional drought while the entire country was facing its longest 12 month period in a drought since 1895."
India is "similarly experiencing a very serious droughts with countrywide rainfall of 17 per cent below normal. In Punjab, India’s breadbasket, rainfall was 70 per cent below normal."
According to the WMO, "severe drought also developed in parts of East Africa in late 2010 and continued through most of 2011 with the most severely affected areas encompassing the semi-arid regions eastern and northern Kenya, western Somalia, and southern border areas of Ethiopia.
In 2009, international climate experts gathered at the International Workshop on Drought and Extreme Temperatures in Beijing released their climate projections for the 21st century, forecasting an increase in the frequency of severe droughts in the continental USA and Mexico, the Mediterranean Basin, parts of northern China, across southern Africa and Australia and in parts of South America."
The world's best food producing regions are the Northern Hemisphere (NH)
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