The effects of climate change on vegetation affected by the weather?

by Michael Smith

“The clock of climate change is ticking ever faster towards midnight. We are simply not reacting quickly enough” HRH The Prince of Wales

A very interesting statement by His Royal Highness but the question is, is climate change something we have any influence over... even though this may not be completely to discussion in this piece.

Climatological and environmental research has led scientists to expect global warming and other climate changes to occur within the next few decades. The causes seem to be man-made, so it is claimed. I say purposely “so it is claimed” for the Earth's climate has been going through these patterns, around every thousand or so years, for ever and a day.

One question is what influence, if any, a warmer climate will have on flora and vegetation in the areas where we live, regardless of where that may be.

The most important ecological results of these effects is higher temperatures. Cities are “heat islands” or “hot sports” on the surface of the Earth. How much higher the temperature is depends very much on the size of the city; the difference can reach 12degC on clear days, or 1degC to 2degC in yearly mean temperature. Climatic conditions within a city can vary considerably, depending on such factors as an area's location within the city; its type of construction and paving; its density of buildings and the emanation of heat from them and especially, its distance from large tracts of vegetation.

Different climate zones, usually more or less concentric, can be distinguished within a city. A city's internal heat islands usually coincide with its built-up areas, but changes in wind direction can temporarily heat other areas as well. The warmer climate in cities is associated with the following:

A shorter none growing season (time between first and last frost) and less severe frosts

A reduction in the number of frost days (to nearly half the normal amount and snow days.

This warmer climate has the following effects on the vegetation in cities: a longer growing season (e.g., in Vienna, by about 10 to 20 days yearly) a shift in phenological phases.

Urban areas of central Europe are experiencing a retreat of native species and archaeophytes. Ate the same time they are and will continue to be centers of introduction and have an abundance of newcomers. The origin of those new species is primarily the warmer regions of Europe, Asia and the Americas.

There must be a few questions here that one must look at. One of those would be: is this all really such a band thing? Could we not make use of such climatic advantages and, for instance, use roofs and other spaces within towns and cities where to grow vegetables that could do with a longer growing season or simply in order to supply the demand by people for local foods.

Certainly there are ways of utilizing cities too for a variety of purpose of growing foods and this is being done already in some places. We just need more of that. There are enough unused spaces, including roofs, that could be utilized.

While there then would be food grown locally the growing of such plants would also reduce the temperatures then in those heat islands of the city somewhat, of that we can be more or less certain.

In addition to the food we should also add trees to the cities and towns, as those especially would reduce the heat and, if fruit trees, could also add to the food and reduce the food miles of fruit and vegetables in the shops.

Most cities and towns do have municipal parks and some even municipal woods and forest. Those could also be utilized for wood production even and especially as a climate controller. Burning wood is carbon neutral as the wood burned for heating and power generation only releases that amount of carbon dioxide that is has stored over its lifetime. Leaving fallen trees to rot, however, releases both carbon dioxide and also methane, the latter being more dangerous a greenhouse gas than carbon dioxide, without giving any benefit to us. Hence we need to have to return to the old ways of managing woods.

But, I digressed again a little.

However, trees in cities and plants of various kinds can have a beneficial impact of the local climate of those and can reduce the impact of any climate change that may be happening.

© M Smith (Veshengro), 2009