Earlier this year I published my own ‘State of the Climate’ for 2014, looking at the global conditions for a variety of issues, for want of a better word, that have been projected to worsen due to climate change. The issues I previously examined were conflict deaths, overall climate deaths, climate refugees, recent trends in agricultural production, biodiversity (well, polar bear populations) and crude mortality indexes, and a look at trends for the planet’s major ice aggregations, sea level, major storms and drought. (I was unable to get to complete data sets for many of the indicators, showing some U.S. only figures and data for previous years for some categories.)
Before I turn to an examination of flooding trends, the quick summary of those previous posts is that if climate change is going to have an impact on any or all of these factors, it has not shown up yet in the data.
- Conflict deaths have fallen by two different measures
- The total number of refugees has risen, but they are pretty clearly conflict refugees, not climate victims
- Polar bear populations appear to be in rude good health
- Roger Pielke Jr. is right in saying that there is as yet no discernible climate signal in data regarding storms
- Sea level is rising at 3 mm / year, (an increase from previous measurements of 2 mm / year. The current rate would amount to one foot of sea level rise this century if maintained
- Arctic ice is one standard deviation below its 30 year average, while Antarctic sea ice is two standard deviations above.
However, complacency on the part of some due to this flow of encouraging news is perhaps unwarranted, as the most dangerous ‘natural disaster’ seems to be occurring more frequently and taking more lives. The region most affected is Southeast Asia.
So, on to floods. As with drought, I am as yet unable to get data past 2009, so this is actually a review of part of what is called the ‘recent warming period’ that includes 14 of the 15 highest temperature years, all of which came after 2000.
Floods are the leading cause of natural disaster deaths worldwide and were responsible for 6.8 million deaths in the 20th century. Between 1980 and 2009 there were almost 540,000 deaths due to flooding. Part of the increased mortality (but certainly not all) is due to rapid population growth in areas vulnerable to flooding. Pakistan, which had severe flooding a few years ago, has grown in population from 32 million to 187 million when the flood occurred in 2010. Low lying coastal areas in SE Asia are perhaps the most vulnerable areas in the world–and that is precisely where populations have been increasing rapidly.
The Dartmouth Flood Observatory maintains a database that currently holds records for 3,704 significant floods worldwide from 1985 through August of 2010. (The DFO database provides a comprehensive list of flood events recorded by news, governmental, instrumental, and remote sensing sources from 1985 to 2009. Inclusion criteria are: significant damage to structures or agriculture, long intervals since the last similar event, or fatalities. Flooding specifically related to hurricane storm surge and tsunamis were excluded.)
The number of reported floods has increased dramatically. However, much of the increase is a statistical artifact due to increased availability of information–more floods are happening, certainly, but also more floods are being reported. I don’t want this to sound weaselly–floods are more common now than in the early 80s. But I don’t know how much more common.
Looking at impacts for two periods–from 1985 to 2000 and from 1998 to 2009 (which is part of the period that has 14 of the warmest 15 years on record), we see:
Deaths 1985 – 1998 -246,077
Deaths 1999 -2009 – 374,324
The peak year between 1985 and 2009 for the global incidence of major floods was 2003, with 290 reported floods.
1985 – 69
1986 – 46
1987 – 46
1988 – 111
1989 – 111
1990 – 103
1991 – 124
1992 – 110
1993 – 99
1994 – 107
1995 – 110
1996 – 103
1997 – 156
1998 – 184
1999 – 101
2000 – 102
2001 – 170
2002 – 261
2003 – 290
2004 – 200
2005 – 167
2006 – 232
2007 – 244
2008 – 172
2009 – 167