Data vs. Models #3: Disasters

Addendum at end on Wildfires

Looking Through Alarmist Glasses

In the aftermath of COP21 in Paris, the Irish Times said this:

Scientists who closely monitored the talks in Paris said it was not the agreement that humanity really needed. By itself, it will not save the planet. The great ice sheets remain imperiled, the oceans are still rising, forests and reefs are under stress, people are dying by tens of thousands in heatwaves and floods, and the agriculture system that feeds 7 billion human beings is still at risk.

That list of calamities looks familiar from insurance policies where they would be defined as “Acts of God.” Before we caught CO2 fever, everyone accepted that natural disasters happened, unpredictably and beyond human control. Now of course, we have computer models to project scenarios where all such suffering will increase and it will be our fault.

For example, from an alarmist website we are told:

Human-induced climate change has already increased the number and strength of some of these extreme events. Over the last 50 years, much of the U.S. has seen increases in prolonged periods of excessively high temperatures, heavy downpours, and in some regions, severe floods and droughts.

By late this century, models, on average, project an increase in the number of the strongest (Category 4 and 5) hurricanes. Models also project greater rainfall rates in hurricanes in a warmer climate, with increases of about 20% averaged near the center of hurricanes.

Looking Without Alarmist Glasses

But looking at the data without a warmist bias leads to a different conclusion.

The trends in normalized disaster impacts show large differences between regions and weather event categories. Despite these variations, our overall conclusion is that the increasing exposure of people and economic assets is the major cause of increasing trends in disaster impacts. This holds for long-term trends in economic losses as well as the number of people affected.

From this recent study:  On the relation between weather-related disaster impacts, vulnerability and climate change, by Hans Visser, Arthur C. Petersen, Willem Ligtvoet 2014 (open source access here)

Data and Analysis

All the analyses in this article are based on the EM-DAT emergency database. This database is open source and maintained by the World Health Organization (WHO) and the Centre for Research on the Epidemiology of Disasters (CRED) at the University of Louvain, Belgium (Guha-Sapir et al. 2012).

The EM-DAT database contains disaster events from 1900 onwards, presented on a country basis. . .We aggregated country information on disasters to three economic regions: OECD countries, BRIICS countries (Brazil, Russia, India, Indonesia, China and South Africa) and the remaining countries, denoted hereafter as Rest of World (RoW) countries. OECD countries can be seen as the developed countries, BRIICS countries as upcoming economies and RoW as the developing countries.

The EM-DAT database provides three disaster impact indicators for each disaster event: economic losses, the number of people affected and the number of people killed. . .The data show large differences across disaster indicators and regions: economic losses are largest in the OECD countries, the number of people affected is largest in the BRIICS countries and the number of people killed is largest in the RoW countries.

Fig. 3 Economic losses normalized for wealth (upper panel) and the number of people affected normalized for population size (lower panel). Sample period is 1980–2010. Solid lines are IRW trends for the corresponding data.

Fig. 3
Economic losses normalized for wealth (upper panel) and the number of people affected normalized for population size (lower panel). Sample period is 1980–2010. Solid lines are IRW trends for the corresponding data.

The general idea behind normalization is that if we want to detect a climate signal in disaster losses, the role of changes in wealth and population should be ruled out; however, this is complicated by the fact that changes in vulnerability may also play a role. . .(After extensive research), we conclude that quantitative information on time-varying vulnerability patterns is lacking. More qualitatively, we judge that a stable vulnerability V t, as derived in this study, is not in contrast with estimates in the literature.

Climate drivers

Historic trend estimates for weather and climate variables and phenomena are presented in IPCC-SREX (2012, see their table 3-1). The categories ‘winds’, ‘tropical cyclones’ and ‘extratropical cyclones’ coincide with the ‘meteorological events’ category in the CRED database. In the same way, the ‘floods’ category coincides with the CRED ‘hydrological events’ category. The IPCC trend estimates hold for large spatial scales (trends for smaller regions or individual countries could be quite different).

The IPCC table shows that little evidence is found for historic trends in meteorological and hydrological events. Furthermore, Table 1 shows that these two events are the main drivers for (1) economic losses (all regions), (2) the number of people affected (all regions) and (3) the number of people killed (BRIICS countries only). Thus, trends in normalized data and climate drivers are consistent across these impact indicators and regions.


People who are proclaiming that disasters rise with fossil fuel emissions are flying in the face of the facts, and in denial of IPCC scientists.

Trends in normalized data show constant, stabilized patterns in most cases, a result consistent with findings reported in Bouwer (2011a) and references therein, Neumayer and Barthel (2011) and IPCC-SREX (2012).

The absence of trends in normalized disaster burden indicators appears to be largely consistent with the absence of trends in extreme weather events.

For more on attributing x-weather to climate change see: X-Weathermen Are Back

Addendum on Wildfires

Within all the coverage of the Fort McMurray Alberta wildfire, there have also been lazy journalists linking the event to fossil fuel-driven global warming, with a special delight of this being located near the oil sands.  The best call to reason has come from A Chemist in Langley, who argues for defensible science against mindless activism.  Of course, he has taken some heat for being so rational.

Here is what he said about the data and the models regarding boreal forest wildfires:

Well the climate models indicate that in the long-term (by the 2091-2100 fire regimes) climate change, if it continues unabated, should result in increased number and severity of fires in the boreal forest. However, what the data says is that right now this signal is not yet evident. While some increases may be occurring in the sub-arctic boreal forests of northern Alaska, similar effects are not yet evident in the southern boreal forests around Fort McMurray.

My final word is for the activists who are seeking to take advantage of Albertans’ misfortunes to advance their political agendas. Not only have you shown yourselves to be callous and insensitive at a time where you could have been civilized and sensitive but you cannot even comfort yourself by hiding under the cloak of truth since, as I have shown above, the data does not support your case.



  1. Hifast · May 9

    Reblogged this on Climate Collections and commented:
    Excellent post from Ron Clutz.
    The cited study is here:


  2. craigm350 · May 9

    Reblogged this on WeatherAction News.


  3. erl happ · May 9

    Thank you for taking the trouble to put the garbage out.


  4. joekano76 · May 9

    Reblogged this on TheFlippinTruth.


  5. manicbeancounter · May 15

    The Chemist at Langley has a valid point. Any sensible people should not make political capital out of natural disasters. But weather-related disasters are usually used in this context. Here in Britain last December there was extremely high rainfall, especially in the Lake District, with consequent flooding. This was held as the sort of thing that would become more common under climate change. The human impact was quite severe. It was played down that the dredging of rivers had been reduced in recent years to enable the rivers to follow their natural course. On a flood plain, that natural course is to meander across that plain. If people have located there believing the river course will not change, then their properties will get flooded without the maintenance.


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