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Investigate the signs of Spring with Greenwave!

Although the Greenwave project will not be going ahead this year you and your class can still look out for the signs of spring in your local area. There are a range of resources to help so why not:

  • Use the Spotters Guide to observe common species like the frog, primrose and horse chestnut in your area, as they react to the warmer, longer days.
  • Observe and record weather in your area over the coming months; click below for resources to help with measuring temperature, wind speed and rainfall.

 

Long before the advance of science and development of sophisticated means of measuring the weather, people have attempted to predict what conditions the near and long term future holds in store. Knowing what to expect has always been essential for the purpose of caring for animals and growing food, as well as trying to anticipate a particularly cold winter or dry growing season.

Over generations various natural indicators from the weather itself, atmospheric conditions or the behaviour of animals have been identified by people around the world that they believe give an indication of weather to come.

For example if cattle lie down and refuse to go up hill to pasture this has been seen as an indication that stormy weather is approaching. Similarly if your cat sits or lies with her back to the fire you can expect a cold spell. The nursery rhyme line "A swarm of bees in May, is worth a load of Hay" suggests that if there are lots of bees about during the late spring then there will be good crop growth during the summer.

In the United States, the black and orange coloured woolly bear caterpillar has long been used to predict the severity of the coming winter. It is thought that the wider the black bands on the caterpillar's back are the harsher the winter will be.

While many of the traditional phrases and proverbs associated with weather prediction do not stand up to scientific scrutiny, some of them do seem to be useful for predicting what might happen over the next few hours. Some examples of these are below:

  • Sometimes a circle appears around the sun or the moon. This circle or halo is visible when the light from the sun or moon is passing through the ice crystals that form very high level cirrus and cirrostratus clouds in the sky. These clouds do not carry rain themselves but often come before a low pressure weather system that may bring rain with it. This saying may also appear in the following form: "When halo rings the moon or sun, rain's approaching on the run."
  • "When smoke descends, good weather ends." If the smoke from a chimney does not ascend into the sky but instead curls back down towards the ground this may indicate that there is a lot of moisture in the air and that a change in the weather for the worse may be due.
  • "Red sky at night shepherds delight. Red sky in the morning shepherds warning." This is one of the most common weather sayings, and it can often be proved true for the following reasons. Firstly, our weather systems generally come from a westerly direction. Secondly, the colour of the sky is caused by the light of the sun being split into different colours as it passes through the dust and water vapours that occur high in the atmosphere.

When we see a red sky in the evening this means that the sun's light is shining through a large amount of dust particles. This usually indicates good stable weather with high pressure coming from the west.

On the other hand, when the sky is red in the morning as the sun rises in the east, this may indicate that a good weather system has just passed to the east, to be followed by a pattern of less stable conditions.

We have been hearing a lot about climate change and global warming recently - but do you know what exactly is happening?

The earth is heated by long red rays of heat that enter our atmosphere from the sun. These rays bounce off the earth and are reflected back out into space through the atmosphere. If all the heat escaped back out we would be very cold indeed here on earth. However the carbon dioxide in the atmosphere is able to hold on to enough heat to make life on earth possible. How warm the earth is depends on how much carbon dioxide there is in the atmosphere to hold on to the heat.

Two hundred years ago the measurement was 270 parts per million. Carbon dioxide is taken in by plants when they are growing. Their green leaves, in the presence of sunlight, are able to split the carbon dioxide molecule in the air. The plant takes in the carbon part and releases the oxygen part into the atmosphere. All plants are made of carbon - trees, for example, take a lot of carbon out of the atmosphere as they grow and keep it in their trunks and branches.

How does carbon get back into the atmosphere?

When the trees and plants die and rot away, the carbon in their trunks and branches is released back into the atmosphere. It is taken in when they are growing and released when they die and rot away - the Carbon Cycle.

However, not all plants rot away when they die. If the conditions are not suitable for decay, say because of lack of oxygen or because conditions are too acidic, then the dead plants will just stay there. We see this in Ireland today in our bogs. Turf is made from plants that lived two or three thousand years ago but could not rot when they died because conditions were not right. Turf is called a fossil fuel. Similarly coal, oil and natural gas are made from plants that lived millions of years ago - in the Carboniferous Era - but could not rot away because condition were not suitable. All the carbon they took in from the atmosphere when they were growing is still stored as coal, oil or gas in these deposits.

When timber or any of these fossil fuels is burnt, however, the carbon they contain is put back into the atmosphere by the burning process. Since the Industrial Revolution we have been burning vast quantities of coal, oil and gas and the amount of Carbon Dioxide in the atmosphere has increased. There is now 380 parts per million of Carbon Dioxide in the atmosphere - an increase of 40% over the last two hundred years. So more heat is being held by this Carbon Dioxide - known as greenhouse gas - because it acts like the glass in a greenhouse holding in the heat.

The world is warming up - what is called Global Warming - and it is causing climate change. The ten hottest years on record on earth have all happened since 1995, with 2005 being the hottest year since records began. Polar ice caps and glaciers are melting at a faster rate because of this increased temperature.

The planet is two thirds ocean and one-third land, so it doesn't heat up evenly. Wind patterns are altered and as a result times of rain and drought are affected. Ocean currents are affected too. In Ireland we are kept warmer than we should be by the Gulf Stream, a warm ocean current that comes to our shores from warmer waters in the South Atlantic. Directly across the Atlantic - Newfoundland, at the samer latitude as us, is kept colder than it should be by the Humbolt Current, which flows down past its coast from the Arctic Ocean. If climate change causes these currents to stop or change direction, Ireland could in fact get much colder.