Revealing the past

Climates are changing constantly, but slowly. Even the present global warming, which many people fear may eventually amount to a significant shift in climate, is measured by the extent to which temperatures might rise over the course of a century. The timescales are longer than a human lifetime. This makes them difficult to comprehend, because the weather we experience today is little different from the weather our grandparents knew, so it is hard to detect any change at all.

If we are to understand them, we need to compare changes that may be occurring now with changes that have taken place in the past. This presents us with a further problem. Written records of the weather are few and far between, and most of them describe conditions in particular places that are widely but unevenly scattered. There are some old weather records for parts of Europe and North America, but many fewer for Africa and Asia, and none at all for the oceans outside the main shipping routes. To make matters worse, records from different places and different times are not based on standardized measurements. Different instruments were used, and readings were taken in different ways and at different times of day, so it is difficult to compare the records from one place with those from another. It is almost impossible to draw conclusions from them about the climates of entire continents, far less that of the whole world.

Inadequate though they are, even these records provide information about only the last few centuries. Accounts of the weather in the 19th or even the 17 th centuries may be useful, but accounts earlier than that are very sparse and usually refer only to extraordinary events, such as severe storms or droughts, that are neither typical nor very helpful. Obviously, there are no written records of any kind to tell us what the weather was like or how the climate was changing hundreds of thousands of years ago. Yet we need to know about processes that operate over thousands of years.

We need other, more reliable sources of information. Obtaining it seems impossible, but it is not. Paleoclimatologists—scientists who study the climates of ancient, prehistoric times—use proxy measurements to reveal details of climate. These are not measurements of temperature or precipitation, but of things that were caused by the weather and from which the weather conditions can be deduced.

Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

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