Taking the vital signs of planet Earth
Sunday, June 8, 2014
The evidence is clear that the Earth is warming and that the impacts will reach to every corner of the planet. If the current vital signs are any indication, we had all better pitch in to muck out the stalls and fast
by PHIL CHADWICK
The planet is large. The 4.54-billion-year-old planet Earth has a radius of 6,371 kilometres, a mass of 6x10exp24 kilograms (that's a six followed by 24 zeroes) and a surface area of 510,072,000 square kilometres. It is almost unthinkable that anything mankind might do could have any impact on the health of something so enormous. A review of the facts, as accurate as modern science can determine them, is like taking the vital signs of planet Earth.
Although the planet might be large, the atmosphere, oceans and ecosystems that support life are really quite small. The atmosphere is like a thin mixture of gases on the planet as thin as the skin on an apple. The part where we all live is less than eight kilometres deep and this wouldn't even be a visible part of the apple's skin without a microscope. Nitrogen (78 per cent) and oxygen (20.6 per cent) comprise most of this atmosphere by volume. A dozen or more other gases make up the rest (1.4 per cent). Half of these are important "greenhouse" gases which moderate the temperatures and make the earth habitable.
So what has happened? Why climate change? Humans started to exploit and consume resources like never before, starting around 1850 with the Industrial Revolution. Railways, steel, petroleum, cars and the age of consumption really got going. World wars sped up this consumption of resources. Burning fossil fuels released carbon that had been locked up for eons back into the atmosphere.
This greenhouse gas can upset the delicate temperature balance in the atmosphere. Since 1850, the concentration of carbon dioxide in the atmosphere has almost doubled. The highest ever atmospheric carbon dioxide concentration (using proxy estimates) had been 300 parts per million (ppm), with the average closer to 220 ppm. Direct measurement since 2005 started the carbon dioxide concentration at 378 ppm and that number has climbed to 397 ppm in just seven years.
Other greenhouse gases were let out of Pandora's Box as well, including methane and the chlorofluorocarbons (CFCs). CFCs also negatively impact the upper ozone layer, but that is another story. Greenhouse gas emissions are reaching new record high levels each year instead of declining.
Deforestation is one of the major causes of climate change. Tropical deforestation is responsible for approximately 20 per cent of world greenhouse gas emissions. Slash-and-burn deforestation techniques are not environmentally friendly. Actively growing trees do indeed remove carbon from the atmosphere, but the decay or burning of the wood releases it right back.
With the forests gone, the exposed soils release carbon reserves and absorb more heat from the sun, accelerating temperature increases. Without evapotranspiration from the forests, atmospheric moisture – and thus precipitation – is decreased. A study in deforested north and northwest China found that the average annual precipitation decreased by one-third between the 1950s and the 1980s. When rain does occur, the warm and dry soils are susceptible to flooding and mudslides, which further degrade the environment.
The impacts of greenhouse gases on temperature are challenging to measure since the heating is not uniform around the globe. According to a report led by the National Oceanic and Atmospheric Administration (NOAA), 2012 ranked eighth or ninth among the 10 warmest years on record, depending on the data set. Worldwide, 2001-2010 was the warmest decade on record since thermometer-based observations began. The global land-ocean temperature anomaly index has risen by 0.6 degrees Celsius since 1945. Climate models that include the best available science predict that temperatures will rise between one and five degrees Celsius by 2100.
Okay, it is not an exact science and there are many variables. Temperature increases will not be uniform and higher temperatures can be expected over the land as compared to over the ocean; and over the Arctic as compared to the equator.
The Canadian Arctic has been warming up four times faster than the equator. By June 2012, snow cover had fallen to its lowest levels since records began. The low snow cover observed was 18 per cent lower than the previous record set in 2007, and a shocking 54 per cent lower than the 1980 snow cover observation. The record or near-record values being observed in the Arctic are no longer anomalies or exceptions but are the new norm that we can expect to witness for the foreseeable future.
The absence of reflective snow and ice allows the sun's energy to be absorbed by the darker surfaces, thus accelerating the impacts of the other contributors to climate change. As mentioned in a previous article for Better Farming, the consequent weakening of temperature contrast from the equator to pole has resulted in a 14 per cent decrease in the mean speeds of the jet stream since the 1990s. The atmosphere becomes dominated by blocking patterns like those in a meandering stream. Such patterns create weather that is challenging to forecast and potentially severe.
A warmer atmosphere can also hold more moisture. Basic theory, observations and climate model results all show that the increase in water vapour is roughly six or seven per cent per degree Celsius warming of the lower atmosphere. This is consistent with recent observations that estimate five per cent more water vapour in the atmosphere as compared to long-term averages. Water vapour itself is another greenhouse gas. From a meteorologist's perspective, I have recently analyzed air masses with moisture values far higher than I ever saw at the start of my career in the 1970s. The impacts on rain rates and storm character are significant.
Both heat and moisture are energy and this increased power can generate weather meteorologists have never seen before. In 2012, "Superstorm Sandy" caused over $68 billion (2013 U.S. dollars) in damage and at least 286 people were killed along the path of the storm. In 2005, Hurricane Katrina caused $81 billion (2005 U.S. dollars) in damage and at least 1,833 people died in the hurricane and subsequent floods. Insurance companies are at a loss about what to do with the weather.
Sea ice is decreasing by 12 per cent per decade. The Arctic lost record amounts of sea ice in 2012 and is changing at an unprecedented rate. By September 2012, sea-ice cover had retreated to its lowest levels since the beginning of satellite records, falling to 1.32 million square miles. Around 2000, researchers predicted that the Arctic could experience ice-free summers by the end of the century. New research suggests that ice-free summers will come by 2050 or even sooner.
On 11 July, 2012, Greenland experienced surface melting on 97 per cent of the ice sheet. Greenland has lost 100 million tons of land ice in recent years. Glaciers have continued to shrink worldwide. Ice melt from land is a major contributor to sea level rise. Global sea levels rose to record highs in 2012, after being depressed during the first half of 2011 because of the effects of La Niña. "Over the past seven years, it appears that the ice melt is contributing more than twice as much to the global sea level rise compared with warming waters," according to Jessica Blunden, a climatologist at NOAA's national climactic data centre.
The 2012 average global sea level was 34 millimetres above the 1993-2010 average. The mean sea level of the increasingly acidic oceans is now rising at a rate of three to four millimetres a year. This is up from earlier estimates of 1.7 millimetres per year. The increasing acidity of the oceans and its impact on coral reefs is also cause for concern.
Just think what impacts a higher sea level will have! In 2007, Deborah Balk, the acting associate director of the Institute for Demographic Research at the City University of New York, used satellite data to map out places along the coast that have low elevations – less than 10 metres above sea level. Using census figures from 224 countries, Balk showed that low-elevation areas are home to 634 million people – about one in 10 people in the world. Rising sea levels, tides and storm surges will put all of these people at risk.
2012 also saw record warm permafrost temperatures in Alaska and in the Canadian Arctic. Methane gases were locked in the permafrost when the planet was a much different place with constant volcanoes and dinosaurs. This methane is about to be released into the atmosphere by the thaw. In 2010, methane levels in the Arctic measured twice as high as at any time in the 400,000 years prior to the industrial revolution.
Methane is an important greenhouse gas with a global warming potential of 25 times that of carbon dioxide. Chemical interactions of methane with some aerosols increase its global warming potential. Methane has a larger effect but a shorter net lifetime of 8.4 years in the atmosphere. Carbon dioxide may have a smaller effect, but it has a much longer net lifetime of 100 years in the atmosphere. Methane is typically burned, so CO2 is released into the atmosphere instead of methane. There is potential for technology to burn methane in a productive way to create electricity.
Plants, animals and ecosystems are changing. Possums are marsupials that tend to die if they can't find shelter at minus 15 C – their hairless tails freeze and gangrene sets in. Possums are spreading northward into Ontario's cottage county. Ticks and the associated Lyme disease are now part of life for much of Ontario. Red foxes are making their way into the Canadian Arctic and out-competing the native Arctic fox. Grizzly bears are breeding with polar bears to produce the hybrid "grolar." I am not making this up. The ecosystems are simply changing in response to climate.
What about agriculture? Farming in Ontario will, by necessity, become more like farming in current day Kentucky. Water, drought, precipitation patterns, energy supplies and a host of other commodities that control farming practices will challenge farmers to adapt. Insect pests and new crop diseases are bound to be important concerns with a warming and changing climate.
The planet and all of its interacting and complex systems is indeed a very complicated home. It is undeniable that there is still much to learn about just how all of the pieces fit together. There are certainly doubts generated by the complexity of it all. Doubts lead to confusion and confusion leads to dithering and inaction. Meanwhile, the observed trends continue to escalate beyond the next political horizon.
That climate has changed and that humans are responsible can be stated with a 95 per cent confidence level, according to the International Panel on Climate Change (IPCC). The earth is warming and the impacts reach to every corner of the planet. The evidence is clear. Everyone is affected, but some way more than others. Finger-pointing, denial and argument are not helpful.
In the final analysis, the questions and answers are really quite simple. We all share a responsibility to each other not to harm our fellow inhabitants on this planet. Resources are not boundless and most of those essential commodities are getting harder to find and more challenging to extract. The pollution that results from the exploitation of these resources becomes the responsibility of those who enjoy the riches flowing from them.
A carbon tax is a first step in assigning these costs and it is to be seen who they will be charged to – if such a controversial measure ever gets enacted. My guess is that we will all share in this expense and perhaps that is appropriate. We all enjoy benefits from these resources, so we probably also need to help clean up this mess.
Farmers know that, if you want to enjoy the produce from your livestock, you also have to get down and dirty and muck out the stall. The planet is no different and, if the current vital signs are any indication, we had all better pitch in to muck out the stalls and fast – if for no other reason than it is the "right thing to do" for us, our planet and future generations. Otherwise, the planet as we know it will most certainly die. BF
Phil the forecaster Chadwick has been a professional meteorologist since 1977, specializing in training, severe weather and remote satellite and radar sensing.
