Autumn

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Or Fall as it is also called.

About this time of year in the Northern hemisphere (and six months before or after in the Southern hemisphere) experience a change in season from Summer to Autumn. The nights start to last longer than the days, and the further north you go the shorter the days get.

The heat from the Sun cannot warm the North as much, so as the heat of the day dissipates into the atmosphere as the sun sets the temperature starts to drop.

In towns where buildings hold on to heat the temperature at night can be a few degrees warmer than in the countryside.

Now comes the season of “mists and mellow fruitfulness” and when there is a high pressure system over the land and the winds and breezes drop. Then on cold mornings a mist or fog can be caused by moist air close to the ground.  Sometimes the mist is accompanied by frosts and leaves falling from the trees can glisten with ice crystals as the sun breaks through the clouds.

Each day and night the chlorophyll is sucked from leaves back into the main body of the plants leaving yellow and red pigments behind such as xanthophyll.

These days, with global warming, the leaves stay on the trees for weeks longer. In my childhood they would all have fallen by 5th November when we have bonfire night here in Britain, now they can still be on the trees by the end of that month.

One problem this causes is that we get storms from the Atlantic which rush across the country. They can buffet the trees and the leaves act like sails.

We have had violent winds that tear limbs from trees and even blow them over. There gave been a series of storms which have done damage over the last few years. There is also a strong link between plant diseases and warming of the atmosphere. As the temperature rises sickness such as Sudden Oak death and Ash die back are moving up the country.

A report today by scientists stated that the world is set to overshoot  its 1.5°Celsius target of global warming and may exceed 2°C or even 3°C.

The changing seasons could have a devastating effect on the world. We may enjoy the beauty of fall but we should guard that world for our children and their children’s children.

Tide

Time and tide wait for no man

Tidal reef,

High tide……

Why tide?

The Moon pulls on the Earth and the Earth pulls on the Moon. They are gravitationally linked so that one face of the Moon always faces us and the water in our oceans is attracted upwards towards it by its gravity. On the other side of the world there is also a rise in the waters because there is less gravitational pull on the oceans because they are futher away from the moon…..

Why high tides?

The water is pulled up so far by the moon, but as water flows inwards towards the land as the tide comes in it can also rise further if it is pushing into a narrowing area such as a gap between two islands or into the narrowing channel of a river or stream. In this case sometimes the water can overtop the banks if it is a particularly high tide, such as a spring tide. The water will rise higher if it is forced into the estuary by wind as well as tidal forces.

One third of the world’s population live on various coast lines around the world. If the world continues to warm up then these people will be at risk from the rising tides caused by global warming. Many countries have built costal defenses but these are being damaged every year during stormy weather. Replacing the damaged protective barriers is being abandoned in some places as not cost effective and some costal salt marshes are being recreated to protect the land.