I’m sure you’ve had the experience where you become sick after eating something that was “off” or “didn’t agree with you”. The reason you became sick was there was something toxic in the food you ate or drank, something that had an effect on you within minutes or hours.
Something that has an effect on you within minutes, hours or days is said to have “acute” toxicity. There are many scientific studies showing common environmental and man-made chemicals can be toxic in this way and make animals very sick. These studies also show the dose of a chemical required to make an animal very sick can vary considerably from animal to animal. While genetic differences between the animals are largely responsible for this variability, it’s more complicated than this. How sensitive you may be to an environmental or man-made chemical is not just up to your genetic makeup. You are more vulnerable at certain stages of your life, like during pregnancy or when you are very young. But the story doesn’t end there either.
With acute toxicity you get sick very soon after being exposed to the chemical. That is not the only way a chemical can do harm however. A chemical can also do harm if you are repeatedly exposed to small doses over a very long time. This is referred to as “chronic” toxicity. With chronic toxicity, each small exposure may not produce any immediately apparent ill effects; it is the cumulative effects of the repeated small doses that cause the problem. The death of a thousand cuts was a form of torture and execution practised in Imperial China. None of the individual cuts was fatal but together… Read the rest of this entry »
A month ago we hit an important milestone as a species. It wasn’t some startling new discovery, a medical breakthrough or the completion of a massive engineering project. It was a quiet milestone receiving barely a mention on the evening news. Nevertheless, it was highly significant. With very little fanfare, the world’s human population reached seven billion.
No one knows exactly who the seventh billion person to be born was or where or when they were born. So to mark the event, the United Nations chose October 31 as the date and identified babies in various countries around the globe to act as symbolic heralds for the milestone.
How did we get to this milestone? It’s an important question with a very interesting answer.
It took all of human history to reach 1 billion people in 1800.
It was another 127 years before we reached 2 billion in 1927.
It took 33 more years to reach 3 billion in 1960.
Another 14 years to reach 4 billion in 1974.
Only 13 years to reach 5 billion in 1987.
12 years to reach 6 billion in 1999.
And in 2011 – another 12 years later – we passed 7 billion.
Figures courtesy of the United Nations Population Fund (1).
Look at how fast the population is growing. While it took two human lifetimes to go from 1 to 2 billion, it now takes little more than a decade for the population to increase by the same number. In my lifetime, the world’s human population has increased by over 4 billion.
But growth is a good thing, isn’t it? Shareholders want their stocks, investments and superannuation to go up; we want our houses to increase in value; business owners want greater productivity; employees want more take-home pay and economists and politicians constantly tell us we must have a growing economy to guarantee our future prosperity. So an increasing population must also be good? More people to do the work; more people to buy the goods we make and more people to pay taxes and contribute to the economy. So the faster we grow the better off we are, right? While it sounds great on paper, does it really work that way? Read the rest of this entry »