Food and Water in Crisis
At even 1°C we should expect serious food shortages from droughts floods and storms. Yet even now the six major grain-growing regions do not produce enough surplus for the world's existing populations. One billion people lack access to safe drinking water and over 800 million are mal-nourished. How can we expect to sustain the people of the world when conditions become seriously bad. We are already living well above our carrying capacity, meaning there are not now sufficient natural resources to sustain our way of life.
The map shows the huge areas already suffering from prolonged droughts where people are under-nourished. This includes the two major tropical forest areas.
Agriculture is already under stress. The area of the world stricken by drought has doubled in the past 30 years. The economic costs of global warming are doubling every decade. With severe weather and flooding from rising seas global food supplies would be insufficient.
Besides the heating, the earth has been weakened by the loss of forest and marshland. As heating proceeds much of the tropical land will become scrub and desert, thus adding to the problem.
Some consequences of an increase of 1°C were studied in Australia. It would reduce rainfall in the eastern hills, leading to a 15% drop in the adjacent grasslands. This, in turn, would reduce the average weight of cattle by 12%, significantly reducing beef supply, and dairy cows would produce 30% less milk. Livestock numbers would decrease by 40% at 2°C. As temperatures are projected to rise by 5°C within 60 years, the loss in production will be greater. See Footprints #3.
That means a loss of 90% of core habitat for most Australian vertebrates with the lifetime of any child now in primary school, and six months every year above 35°C in the central states. This would lead to a minimal 50% increase in forest fires.
Other food regions could suffer similar consequences at the same time. The ability to imports food and raw materials will become inadequate as supplies in other regions are overwhelmed. Even in the short term a worldwide drop of 400 million tonnes in cereal crops would be minimal.
The notion that our over-populated society has the ability to adapt and make climate change manageable is unfounded.
Can we use bio-mass to create an alternative to petrol? The weight of all agricultural produce is about half a gigaton (a thousand million tons). If we were to use bio fuel we would need 2-3 gigatons. To grow this we would be using more of the land's surface than we do already. Were we to use the entire Australian wheat crop to make ethanol it would provide only one-third of our fuel needs, whereas this wheat is enough to feed 80 million people. Clearly in the midst of a fuel crisis bio-fuel would not be a viable option, unless prepared for well in advance.
As temperatures rise even further a small human population might survive on agriculture, at least if it reverted to some primitive methods. Most food would have to be produced at a local level. It is even likely that each family will have to produce its own food. That raises important questions for our suburban lifestyle and its need for fuel to run its transport.
Declining water supplies almost everywhere in the tropics and southern hemisphere. Australia's droughts would increase 70% at just 1°C. The impact on Perth (left) has already seriously affected industry.
Together, oceans and plankton absorb about 2 billion tons of carbon annually. During the past 20 years plankton has declined more than 10%. Less plankton means less carbon uptake.
Oceans become denser above 12°C. A stable surface layer of warm water forms and does not mix with the cooler waters below where all the nutrients lie. This barrier denies food to life in the warm layer. As oceans warm so the area covered by nutrient-poor water increases, making the oceans less friendly for algae or plankton. This reduces the amount of carbon the seas can absorb.
Also Plankton is the basis of the marine food chain. This has catastrophic implications for the entire marine habitat, which ultimately relies on plankton at the base of the food chain.
In addition, CO2 emissions are lowering the seas acidity more than has been experienced for hundreds of millennia. The most critical factor is that the rate of change is 100 times greater than at any recent time. It is calculated that the acidification at 2°C would take ten thousand years or more to rectify. This would be another disaster to marine life.
The number of "dead zones" in the ocean have increased by 30 percent in the past two years. These are where pollution-fed algae remove oxygen from the water so that fish find it hard to live. Examples are found off the Mississippi River, the China coast, Japan and Australia. These are becoming major threats to fish stocks.To the top