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.
Melting Ice Caps
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 heatwaves 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.
Feedback Loop from Melting Ice Caps
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 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 the water lost from melting ice caps 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. Melting ice caps therefore provide 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 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, does 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 things get really bad.
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 doesn’t 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 a planetary emergency of this scale, 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 not only promotes rapidly melting ice caps, and rising sea levels, it also causes worldwide drought. 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.