PrintSan Diego Wildfires and Climate Alarmism
Back in May, when wildfires were raging in the San Diego area, a host of mainstream media stories appeared on the subject. In this current edition of climate science reality, we will examine some of the claims that science journalists published and see whether they are accurate.
The New York Times published a piece by Jennifer Medina on May 15 covering the California wildfires, especially those around San Diego. Take this quote:
"We are used to very windy, very hot and dry conditions, but not in May," said Daniel Berlant, a spokesman for the California Department of Forestry and Fire Protection. "It is really unprecedented to have these conditions this early."
Right, because it is never dry during May in California. The month of May 2014 was only the 27th driest statewide in California's climate dataset going back to 1895. Ergo, not even remotely close to a record dry May in California this year. Not a single one of California's seven climate divisions came close to setting a record for low precipitation in May.
California's water year starts in October. Neither the state as a whole nor any of its climate divisions set a record low for cumulative water year precipitation up to May. So, in contrast to what the California Department of Forestry and Fire Protection spokesman said, yes, California has seen just as dry – and even drier – conditions during May than this year.
And very hot conditions in May are unheard of in the Golden State? Nonsense. May 2014 was only the 11th warmest May on record since 1895 in the state, a full 4°F below 2001. Once again, not a single one of California's climate divisions came close to setting a record for the hottest May in recorded history. The average maximum temperature for the state this May was 78.6°F, only the 14th highest on record and a full 5.2°F below the record high from 2001. Not a single climate division in the Golden State came close to setting a record for the highest average maximum temperature during May.
This May is hot and dry in California, but hot and dry conditions in May are not particularly unusual.
Let's examine another quote from this NYT story:
"It's clear that climate change is playing a role," said John Laird, the state's secretary for natural resources. "We are in the middle of the three driest consecutive years since records were kept. We're in extreme drought in 100 percent of the state. There is no part of the state that is not vulnerable."
California is currently "in the middle of the three driest consecutive years since records were kept"? If you are in the middle of three years, doesn't this mean you are 1.5 years into something, with still 1.5 years to go? Apparently the state's secretary for natural resources is able to predict the future.
Perhaps he meant that the past three years up to April 2014 (which would have been the latest climate data available at time of this story's publication) were the driest 36-month period in California "since records were kept"? Oops, they weren't. The period from May 2011 to April 2014 was only the third driest since 1895, beaten by drier periods in 1928-1931 and 1974-1977. You might also be interested to know that there has been absolutely no significant trend in the 36-month precipitation for California ending in April since records began. Not even close. The regression p-value is 0.92 using non-parametric methods and 0.76 using parametric approaches. Almost a perfect non-correlation. But somehow this recent dry spell in California must be due to climate change? No chance. Causation requires correlation, and in this case, we have no correlation whatsoever. Ergo, no causation.
Maybe the secretary for natural resources meant the three driest consecutive calendar years (i.e., ending in December)? If he did, he is still wrong. The calendar year period from January 2011 to December 2013 was only the 8th driest in California's history. Maybe the secretary meant the 3-year drought index for the state ending in April? That was only the 11th lowest on record. Maybe he meant the 36-month calendar-year drought index ending in December 2013? Hmm...that was only the 33rd lowest on record.
Oh well...moving on.
Laird also claimed in this story dated May 15, 2014 that "we're in extreme drought in 100 percent of the state." Really? It was that apocalyptic? Here is the drought monitor for California from May 13, 2014.
Seventy-seven percent of the state was in extreme drought or worse (i.e., D3 or D4 categories), unchanged from the previous week. That is most definitely not 100 percent. There has not been a single point in time during the 2013-2014 water year where 100 percent of the state was in "extreme drought."
The same day as this NYT story of ill science communication repute appeared, Eric Holthaus penned an apocalyptic delight at Slate.com entitled "The Science Behind the Amazing, Terrifying Firenadoes in California" focusing on the fires in San Diego County. According to Holthaus's story, "it didn't take long for local officials to point out the connection to climate change." Indeed, "San Diego Fire Chief Javier Mainar said the unusual weather pattern didn't bode well for the rest of the season. 'It is pretty amazing to see these in May,' Mainar said. 'We certainly have seen climate change and the impact of climate change.'"
Climate change in the San Diego area leading to more wildfires in May? May 2014 was certainly dry as a bone in this area, with no precipitation. Is that unusual? Nope. Out of 141 years of May precipitation records in San Diego, 22 have zero precipitation. In other words, one out of about every six months of May in San Diego record no precipitation. Thus, a bone-dry May isn't even unusual. And no chance of a significant trend in May precipitation for San Diego since 1970 – recall that this is the time period over which the National Climate Assessment tells us climate change impacts should be most evident.
Surely annual precipitation must be declining in the San Diego region, leading to these recent fires? Nope. No significant trend in annual precipitation since 1970, or even since records begin in 1872. It must be water year (October-September) precipitation that is on the decline? Nope. No significant trends in that, either, since 1970 or since 1872.
May 2014 was very warm in San Diego, setting a record (69.5°F) for the warmest May average temperature on record. But so what? For the record to be any indication of anthropogenic climate change, it has to be part of a trend also correlated to atmospheric greenhouse gas concentrations. And there has been no significant trend in May average temperatures for this region since at least 1970. Annual temperatures in the San Diego area haven't increased over the past several decades, either. Actually, there is this inconvenient truth: over the past 40 years, there is a highly statistically significant declining trend – aka, cooling – in San Diego's average annual temperatures.
As I've also previously shown, "since 1970, there has been a highly statistically significant declining – not increasing – trend in summer [June, July, and August] high temperatures for San Diego." For the month of May, we also find undeniably no significant trend in mean maximum temperatures since 1970 (the correlation is negative, not positive). Nor is there a significant increasing trend in mean maximum temperatures since 1970 for April, March, February, or any other month of the year. Actually, February, June, July, August, and December all have significant declining trends in their respective mean maximum temperatures since 1970 – as does the annual value. Average high temperatures are getting lower in San Diego since 1970, not higher. How does that lead to more wildfires?
It must be increasing extreme hot temperatures in the San Diego area over time in May that is causing the fires? Nope. May 2014 didn't even set the highest one-day maximum temperature record for the month. That would be from May 1896, when it reached 98°F. No significant trend in the monthly highest maximum temperature for May since at least 1970.
So precipitation isn't changing, and temperatures (mean, mean maximum, and extreme maximum) are not changing, either – actually, they are generally getting colder on an annual basis since 1970 – and yet climate change is the cause of this year's wildfires in the San Diego area? That simply does not compute.
