I've gone over all this before.
http://somersoft.com/forums/showpost.php?p=1102652&postcount=70
Most of Australia is getting wetter. Most of the world is getting wetter. increased CO2 means increased crop yields which means more food to feed everyone. That's why an extra 40 million tonnes per year of food is being grown each and every year by the worlds farmers on less land. And it will continue. The world has always been able to sustain more life in the warmer wetter periods. Life in the colder dryer times have always ment famine and disease and death.
See ya's.
Sure thing buddy. Leave the science to the scientists.
What would be the effects of an increase of CO2 on agriculture and plant growth in general?
1. CO2 enhanced plants will need extra water both to maintain their larger growth as well as to compensate for greater moisture evaporation as the heat increases. Where will it come from? In many places rainwater is not sufficient for current agriculture and the aquifers they rely on are running dry throughout the Earth (1, 2).
On the other hand, as predicted by climate research, we are experiencing more intense storms with increased rainfall rates throughout much of the world. One would think that this should be good for agriculture. Unfortunately when rain falls in short, intense bursts it does not have time to soak into the ground. Instead, it quickly floods into creeks, then rivers, and finally out into the ocean, often carrying away large amounts of soil and fertilizer.
2. Unlike Nature, our way of agriculture does not self-fertilize by recycling all dead plants, animals and their waste. Instead we have to constantly add artificial fertilizers produced by energy-intensive processes mostly fed by hydrocarbons, particularly from natural gas which will eventually be depleted. Increasing the need for such fertilizer competes for supplies of natural gas and oil, creating competition between other needs and the manufacture of fertilizer. This ultimately drives up the price of food.
3. Too high a concentration of CO2 causes a reduction of photosynthesis in certain of plants. There is also evidence from the past of major damage to a wide variety of plants species from a sudden rise in CO2 (See illustrations below). Higher concentrations of CO2 also reduce the nutritional quality of some staples, such as wheat.
4. As is confirmed by long-term experiments, plants with exhorbitant supplies of CO2 run up against limited availability of other nutrients. These long term projects show that while some plants exhibit a brief and promising burst of growth upon initial exposure to C02, effects such as the "nitrogen plateau" soon truncate this benefit
5. Plants raised with enhanced CO2 supplies and strictly isolated from insects behave differently than if the same approach is tried in an otherwise natural setting. For example, when the growth of soybeans is boosted out in the open this creates changes in plant chemistry that makes these specimens more vulnerable to insects, as the illustration below shows.
6. Likely the worst problem is that increasing CO2 will increase temperatures throughout the Earth. This will make deserts and other types of dry land grow. While deserts increase in size, other eco-zones, whether tropical, forest or grassland will try to migrate towards the poles. Unfortunately it does not follow that soil conditions will necessarily favor their growth even at optimum temperatures.
