Human activities and Global Warming
Are human activities responsible for global warming?
Over the last century and a half global temperatures have risen steadily. Most scientists today believe that humans have caused this global warming by burning fossil fuels.
Many also believe that strong immediate action is required to prevent temperatures to rise to the point where icecaps will melt, coasts will flood, storms will get worse, diseases will spread, animals will die, and more.
But there are still people who maintain that this is a lie, that global warming is not caused by human activities. So let’s have a look at their arguments.
Global warming is not caused by humans:
There are several statements I want to have a look at.
96% of CO2 emissions are from natural sources
This is true.
However Global Warming is not caused by CO2 in the atmosphere, but by an increase in atmospheric CO2.
Carbon dioxide is released to the atmosphere by a variety of natural sources, and about 96% of total CO2 emissions would occur even if humans were not present on Earth.
Although natural sources represent most CO2 emissions, they do not contribute to the recent observed increase in concentrations because natural sources are balanced by natural sinks that remove carbon dioxide from the atmosphere.
The increase in carbon dioxide concentration arises because the increase from human activity is not completely balanced by a corresponding sink.
Today’s carbon dioxide concentrations are not all that high:
This is true.
There has historically been much more CO2 in our atmosphere than exists today. For example, during the Jurassic Period (200,000 years ago), average CO2 concentrations were about 1800 ppm or about 4.7 times higher than today. The highest concentrations of CO2 during all of the Paleozoic Era occurred during the Cambrian Period, nearly 7000 ppm — about 18 times higher than today. Today’s atmospheric CO2 is only nearing 400 ppm, which is extremely low in compairison.
However, we also need to know that at the time that CO2 levels were that much higher than today, temperatures were also a lot higher than today. Human beings did not exist.
Nobody says CO2 levels are abnormally high within the history of our planet. Scientists are simply saying that today’s increase in CO2 levels is due to human activity and that this is causing our climate to warm.
This is probably not a problem for Earth, but it will be a problem for human beings on Earth.
Today’s temperatures aren’t high at all. The last time the planet was this cold an ice age occurred.
This is true.
The Carboniferous Period and the Ordovician Period were the only geological periods during the past half million years when global temperatures were as low as they are today.
Climate change during the Carboniferous Period was dominated by the great Carboniferous Ice Age.
Looking back at the history of planet Earth today’s temperatures are rather cold.
So it’s probably no problem for the planet if the climate warms a few degrees.
We have to remember that scientists are NOT saying warming and cooling aren’t normal for planet Earth.
What they ARE saying is that today’s warming is caused by humans and that therefore it may be possible for humans to stop that warming.
They also say that if we don’t stop the warming, human beings will likely not be able to survive the increase in temperature.
Out of self-preservation we should look for ways to keep the planet relatively cool for as long as we can. Therefore, warming up the planet with our CO2 emissions, is maybe not the best idea.
Other arguments go as follows.