But there are also compounding effects. As more and more forests were converted to arable lands, it changed the world's weather and climates quite profoundly, resulting in even more problems. Everywhere in the world the weather now oscillates between larger extremes of heat, drought, flooding and so on. Such fluctuations do not help sustainability, reason why the soils of our Earth are washing into the seas at an ever increasing rate.

Most of the heat transferred from equator to poles and from sea to the continents happens by winds laden with moisture. Because of the enormous amounts of energy locked up and released by evaporation, condensation and rainfall, air circulation takes care of over 60% of all heat transport on Earth. The remaining part is done by ocean currents. Because of the short-circuit in the water cycle (due to deforestation), less moisture reaches the centres of continents and less heat is dispersed this way, resulting in extremes in temperatures and drought. At the same time, winds increase their intensity (due to higher temperature differences), travelling mainly along continental margins where rains become heavier. These combined changes in weather all over the world bring with them large increases in erosion. In NZ the problem has been exacerbated by the sudden abolishment of subsidies on fertiliser in 1986.

The stable soils of the world that have been cultivated for a long time (many centuries) are not causing undue problems, but as good land became scarce, more marginal lands were opened up in places that were either too steep, too wet, too dry, too hot or too cold. After 50 years (typically) such lands become 'tired' and turn into wastelands with little cover, ready to be washed away into the sea. New Zealand is a classic example of this. Only recently have estimates been made of the soil loss in our country, amounting to over 270 million tonnes per year. But my own observations have shown the amount of soil loss almost to be doubling each decade since the subsidy on fertiliser was abolished in 1986. It was the reason for establishing Seafriends and writing this web site while researching 'Why are we losing so much so fast?'. Please read the soil section to quickly inform yourself.
 
 
 

Deep soils in New Zealand New Zealand has a number of problems arising from its unique situation. Over 60 million years of isolation has given it the non-deciduous Podocarp forests that grow slowly while producing persistent leaf litter which decomposes only slowly. Its mild sea climate produces rain in all seasons, such that soils developed in a continuum of available moisture. As a result, deep subsoils developed underneath the native forests and because of this depth, these subsoils also formed slowly above the underlying bedrock. Natural erosion was unusually low and the marine organisms of NZ evolved in these conditions of clear seas. After deforestation, the top soils provided a rich matrix for grasslands but these top soils eventually thinned, depending on slope and available moisture. As the top soils thinned, the natural fertility was lost and fertilisation became more than necessary. Eventually the subsoil became bare, allowing rain drops to impact directly on the subsoil loams. From here on erosion accelerated rapidly with consequent problems in the sea. Then in 1986 the subsidy on fertiliser was abolished, resulting in underfertilisation of hill country, and a rapid increase in soil loss. Another important factor is the environment's ability to absorb moisture. Native forests retained water on leaves, bark and the very porous top soil. The temperate loams are also able to absorb moisture inside the layered crystal structure of clay. Once forests became pastures, the ability of the environment to store moisture diminished considerably, resulting in increased run-off with associated gully and river erosion. Now the soils are exposed to repetitive cycles of wetting and drying, which is detrimental to soil fertility while also accelerating soil loss.

Is it really serious? It is human nature to remain obtuse (=blind to the obvious) until bad times knock on one's own door. The calls of visionaries and those who have a keen sense of perception remain unheeded as also newspapers do not wish to bring bad news for their advertising revenues. We also have grown used to our problems going away due to the concerted efforts of scientists and the application of new technology. Why should we be worried? The fact that none of our existing mainland marine reserves are working, as they are all degrading, is carefully hushed up and funding is not made available for studying the new threat from degradation. The diagram shown here was compiled from information in a scientific study done for the Department of Conservation (DSIS142), which cost the tax payer over NZ$280,000. It was done to show that marine reserves are working because snappers (Chrysophrys auratus) return after a complete ban on fishing in the Poor Knights Islands, located about 20km out in sea, in late 1998 (after the first sample on the diagram).

Shears NT, Babcock R C (2004): Indirect effects of marine reserve protection on New Zealand's rocky coastal marine communities. DOC Science Internal Series DSIS192 (free on DOC's web site www.doc.govt.nz)
 
 

Note that all the above observations are supported and further explained by our discovery of the Plankton Balance and further discoveries with the Dark Decay Assay (DDA).

In this section we'll discuss the principles behind marine degradation and how it manifests itself, in order to better understand what is going on in the sea.