What is
the impact of these changes in global temperature?
Twenty years ago the scientific community provided evidence and warnings that a global climate crisis was impending, that it was largely man-made, and there were means to slow or reverse the expected consequences.
In those twenty years, very little action has been taken to significantly reduce the magnitude of the global crisis that we face!
The crisis I'm referring to is the steady rise in the temperature of the earth on a global scale. The observed rise is only a few degrees Fahrenheit, and the predicted future rise is similar: a few degrees.
This is what we refer to when we talk about Global Warming.
One of the obvious questions to begin with is this: why is there any concern about a rise in temperature of a few degrees? We live through weather changes of tens of degrees every day and every week. How can such a small temperature change be harmful?
In this post I want to summarize the analyses of thousands of scientists on the impacts of such a small global temperature rise.
In those twenty years, very little action has been taken to significantly reduce the magnitude of the global crisis that we face!
The crisis I'm referring to is the steady rise in the temperature of the earth on a global scale. The observed rise is only a few degrees Fahrenheit, and the predicted future rise is similar: a few degrees.
This is what we refer to when we talk about Global Warming.
One of the obvious questions to begin with is this: why is there any concern about a rise in temperature of a few degrees? We live through weather changes of tens of degrees every day and every week. How can such a small temperature change be harmful?
In this post I want to summarize the analyses of thousands of scientists on the impacts of such a small global temperature rise.
Let's begin with a very simple example of these analyses and conclusions.
Increasing global temperatures are harmful because they cause an increase in the volume of the seas. They also cause the icecaps to melt, and both of these conditions will cause a rise in sea levels.
Why is a rise in sea levels a problem?
Sea level rise increases the vulnerability of coastal populations to flooding and causes land to be lost to erosion. Sea levels have risen 4 to 10 inches this century and are predicted to rise another 6 to 37 inches in the next century.
Hundreds of thousands (and possibly millions) of people will have to relocate and be accommodated by other countries, with consequent political, economic and social impacts on those countries.
Where do these numbers, and predicted consequences come from?
In response to the accumulated evidence being produced by highly respected and qualified scientists around the world, an Intergovernmental Panel on Climate Change (IPCC) was created, which is made up of thousands of climate scientists from around the world. (Go to this link if you want to get an idea of the range of topics studied in relation to climate change.)
These scientists have been making measurements of changes in the temperature and chemical composition of the earth's oceans and atmosphere.
Mathematical models have been developed that lead to predictions of the future chemical and physical state of the atmosphere and oceans, and the subsequent effects on the earth's climate. Their methods have been subjected to continual analysis and improvement in order to produce the best possible predictions of climate change, and the consequences of climate change. (Later in this post I will provide some links to reports issued by the IPPC.)
In addition to sea level rise, another consequence predicted by these scientists, one that will follow the rise of the temperature of the earth's oceans, is an increase in the frequency and intensity of storms such as monsoons and hurricanes.
Think about Katrina. Katrina was not a Global Warming event. However, strong storms in coastal areas can be devastating.
There are currently 46 million people around the world who are at risk due to flooding just from the storm surges that follow intense weather events.
Increasing global temperatures are harmful because they cause an increase in the volume of the seas. They also cause the icecaps to melt, and both of these conditions will cause a rise in sea levels.
Why is a rise in sea levels a problem?
Sea level rise increases the vulnerability of coastal populations to flooding and causes land to be lost to erosion. Sea levels have risen 4 to 10 inches this century and are predicted to rise another 6 to 37 inches in the next century.
Hundreds of thousands (and possibly millions) of people will have to relocate and be accommodated by other countries, with consequent political, economic and social impacts on those countries.
Where do these numbers, and predicted consequences come from?
In response to the accumulated evidence being produced by highly respected and qualified scientists around the world, an Intergovernmental Panel on Climate Change (IPCC) was created, which is made up of thousands of climate scientists from around the world. (Go to this link if you want to get an idea of the range of topics studied in relation to climate change.)
These scientists have been making measurements of changes in the temperature and chemical composition of the earth's oceans and atmosphere.
Mathematical models have been developed that lead to predictions of the future chemical and physical state of the atmosphere and oceans, and the subsequent effects on the earth's climate. Their methods have been subjected to continual analysis and improvement in order to produce the best possible predictions of climate change, and the consequences of climate change. (Later in this post I will provide some links to reports issued by the IPPC.)
In addition to sea level rise, another consequence predicted by these scientists, one that will follow the rise of the temperature of the earth's oceans, is an increase in the frequency and intensity of storms such as monsoons and hurricanes.
Think about Katrina. Katrina was not a Global Warming event. However, strong storms in coastal areas can be devastating.
There are currently 46 million people around the world who are at risk due to flooding just from the storm surges that follow intense weather events.
Yet another consequence of Global Warming will likely
result in an increase in the amount of water exchanged among the oceans, atmosphere, and land.
Increasing rates of evaporation will likely result in drier soils in some regions, (such as the American Southwest) and larger amounts of precipitation and more frequent and severe droughts and floods in other areas.
This prediction has rung true already. In the early '90's, two "100-year floods" (this means floods that are only expected to occur once every one hundred years) occurred in less than 5 years in the Midwestern United States.
Regional water resources will likely be dramatically impacted by changes in availability, distribution, and supply.
Increasing rates of evaporation will likely result in drier soils in some regions, (such as the American Southwest) and larger amounts of precipitation and more frequent and severe droughts and floods in other areas.
This prediction has rung true already. In the early '90's, two "100-year floods" (this means floods that are only expected to occur once every one hundred years) occurred in less than 5 years in the Midwestern United States.
Regional water resources will likely be dramatically impacted by changes in availability, distribution, and supply.
A warming earth will
most likely have a range of largely negative impacts on human health. This will be caused in part by more frequent extremes in temperature.
An increase in mortality from heat stress is likely (e.g. 465 deaths in Chicago during the hot summer of 1995).
Again, there is no claim here that this particular event was caused by Global Warming. The point is that more frequent thermal extremes predicted in the IPCC reports can have tragic consequences, of which the Chicago mortality is just an example.
An increase in mortality from heat stress is likely (e.g. 465 deaths in Chicago during the hot summer of 1995).
Again, there is no claim here that this particular event was caused by Global Warming. The point is that more frequent thermal extremes predicted in the IPCC reports can have tragic consequences, of which the Chicago mortality is just an example.
As a result of warming on a global scale, there will likely be an increase in the geographical range of insect transmitted diseases such as malaria, dengue, yellow fever, and encephalitis.
Currently, 45% of the world's population is within the zone of potential malaria transmission. With predicted temperature increases, there will likely be an additional 50 to 80 million cases of malaria worldwide, bringing the percentage of the world's people living within the susceptible zone from 45 to 60%.
It is also likely that
increasing temperatures will result in increases in the abundance of air pollutants, such as pollen, and mold spores, with a resulting decline in air quality. (Molds grow best in warm damp and humid conditions, and spread and reproduce by making spores.)
An increase in the number of cases of respiratory disease, asthma, and allergies is likely to follow.
The change in the frequency and intensity of extreme weather events will cause floods which contaminate water supplies. Combined with warmer atmospheric temperatures this will lead to the growth of bacteria and the subsequent spread of disease.
An increase in the number of cases of respiratory disease, asthma, and allergies is likely to follow.
The change in the frequency and intensity of extreme weather events will cause floods which contaminate water supplies. Combined with warmer atmospheric temperatures this will lead to the growth of bacteria and the subsequent spread of disease.
In the next 100 years
between one third and one half of the world's mountain glaciers could disappear.
This would greatly reduce the water supply to rivers and thus hydroelectric dams (electric power generation) and agriculture.
Paleoclimate (past climate) data and models show that changing atmospheric temperatures also cause major changes
in ocean circulation. Such changes in ocean circulation can result in rapid and dramatic changes in climate.
Total global food production is not expected to change
substantially as a result of climate change, but production will probably
change dramatically regionally.
Some areas will have increasing crop yields. Others will decline, especially in
tropical and subtropical regions.
The variety of crops that can be grown in a region is predicted to decline. Developing countries that currently struggle with these issues will suffer even more.
The variety of crops that can be grown in a region is predicted to decline. Developing countries that currently struggle with these issues will suffer even more.
These summaries of just a few of the
projected effects of Global Warming, as presented above, are based on IPCC
Technical Assessment Reports (TAR) issued periodically.
These reports are intended to assess scientific, technical and socio-economic information concerning climate change, its potential effects, and options for adaptation to and reduction of the effects.
Here is a link to the most recent report (the largest and most detailed summary of the climate change situation ever undertaken), involving thousands of authors from dozens of countries, and the report states in its summary,
These reports are intended to assess scientific, technical and socio-economic information concerning climate change, its potential effects, and options for adaptation to and reduction of the effects.
Here is a link to the most recent report (the largest and most detailed summary of the climate change situation ever undertaken), involving thousands of authors from dozens of countries, and the report states in its summary,
Warming of the climate system is unequivocal.
Most of the observed increase in global average
temperatures since the mid-20th century is very likely due to the observed
increase in anthropogenic (man-made) greenhouse gas concentrations. In the public arena
the focus has primarily been on carbon dioxide, largely because CO2
is the product of our energy and transportation technologies, and as such is
potentially controllable through new technologies that emit less or no CO2
.
Additional recent
reports (See the EPA report on the effects of global warming on health: http://www.epa.gov/climatechange/effects/health.html
) provide updated projections based on improved climate models, but the lesson
is unchanged.
Global warming is real, it is caused by man, and its consequences, if not reversed, have the potential to be serious, and in some cases disastrous.
It is possible for governments to take steps to mitigate the impacts of some of these threats.
Global warming is real, it is caused by man, and its consequences, if not reversed, have the potential to be serious, and in some cases disastrous.
It is possible for governments to take steps to mitigate the impacts of some of these threats.
A lot of good research and analytical thinking. Very impressive.
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