Lately all over the world earthquakes has increased over the years. Tornadoes, brush fires etc. why dont the government talk about these kind of things. what if something real bad happens one day. I feel like the government never has anything to say which is why I hate them
Chosen Answer:
Natural disasters fall into many different categories, some of which are affected by global warming and some of which aren’t.
Earthquakes are geological events and their has been no significant change in either the frequency or magnitude of these events in recent times. Over the last 40 years there has been a slight increase in the number of large earthquakes of magnitude 6 and above, this has increased from an average of 151 per year to 168; at the same time the total number of earthquakes (mag 2 and above) has decreased from 24777 to 22507 per year. These changes are well within the bounds of statistical variation and nothing should be implied by them.
Earthquake database: http://earthquake.usgs.gov/earthquakes/eqarchives/epic/
The number of meteorological natural disasters has massively increased in recent years, these are the events that can be affected by global warming, but there are other factors involved as well.
For example, in the 1950’s there were just three major forest fires in the world. In the 2000’s that number had gone up to 95. It would be a mistake to claim that global warming was the only reason, we have to look at other factors such as an expanding population, the increased likelihood of arson, forestry management schemes, the number and extent of afforested areas etc.
http://www.grida.no/graphicslib/thumbs/1805c933-493c-4b85-be16-ad06eb342332/large/number-of-major-wild-fires-by-continent-and-decade-since-1950_11d6.jpg
One common mistake is to assume that forest fires only happen when it’s hot. This certainly increases the chances but other factors such as fuel conditions, aridity and humidity need to be taken into consideration as well.
If climate change means that a particular area becomes hotter and drier then the probability of a forest fire happening will significantly increase. So yes, global warming does increase the number of forest fires, but so do many other factors as well.
Events such as heatwaves and floods are primarily dictated by nature, we have very little direct influence upon them. Such events provide more reliable metrics as to how climate change may be affecting us.
If we look at major flooding we find that there has been a six-fold increase in the number of such events since 1950. Whilst humans might affect flooding on a local scale by changing the course of a river or reclaiming floodplains, these events are the major floods that are way beyond the scope of human causation.
http://www.grida.no/graphicslib/thumbs/1805c933-493c-4b85-be16-ad06eb342332/large/number-of-flood-events-by-continent-and-decade-since-1950_10c2.jpg
Similarly we find that there has been a very significant increase in the number of heatwaves. Global warming began to take off in about 1980, in the 100 years prior to this there had only been five major heatwaves, that’s the same number as we’ve had in the last two years. Historically there would have been a major heatwave about once every 17 years, now we have them every two years. Prior to 1980 no heatwave had an official death-toll of over 1,000, since 1980 there have been six such events claiming about 140,000 lives.
http://www.emdat.be/
http://en.wikipedia.org/wiki/List_of_natural_disasters_by_death_toll#Deadliest_heat_waves
Storms are a different matter and it’s difficult to say what effect, if any, global warming is having on them. Storm activity follows a 60 year cycle and we’ve just passed the peak of that cycle. Unfortunately this cycle ties in with the warming trend and this makes it impossible to say how much effect the natural cycle is having and how much is down to global warming. It will probably be another 30+ years before we can confidently say what effect global warming is having.
Storms take their energy from warm waters, if the sea-surface temperature is below 28°C there is rarely enough energy to feed into the storm system. As the oceans warm up the theory is that more energy will be available to create storm conditions so we would expect an increase in both frequency and intensity consequent to global warming. At present there isn’t enough reliable data to back this up.
by: Trevor
on: 8th July 13
