The weather has been unusually cold in the UK over the last few weeks, which has prompted some media comment questioning climate change, and a vigorous response from environmentalist George Monbiot (similar to one he wrote last year) drawing the distinction between 'weather' and 'climate'. As the Met Office writes, this cold snap 'doesn't tell us anything about climate change'.
In his latest article, George Monbiot, attacks this question by John Redwood MP of Jan 5, 2010:
Redwood: Why are we in the northern hemisphere having such a very cold winter this year? Which climate model predicted that?
Miliband: I can hardly believe the question, Mr Deputy Speaker. The weather fluctuates, as everyone knows, and the notion that a cold spell in Britain disproves the science of climate change is something that I believe not even the Right Hon. Gentleman believes.Yet, is Mr. Redwood's question unreasonable? From my perspective, it does not query what is known about climate change. Whilst the climate models often talk about average temperature data (and the Met Office provides a good general sense of what is likely to happen to global temperatures given a high and low emissions trajectory to 2100), Mr Redwood's question seems to be one about variability.
It leads me to think about what kind of weather we might expect in the future, with greater concentrations of greenhouse gases in the atmosphere. Should we expect greater weather temperature variation in a country such as the UK? Is George Monbiot correct in assuming that climate change will mean that he 'might never skate outdoors again' .. or maybe people living in the UK will likely have occasional severe winters?
In a nutshell, this discussion makes me wonder if climate scientists could go beyond describing future temperature average scenarios to describing what weather conditions might really be like in the future given different greenhouse gas concentrations.
And it seems like this is what the Met Office is hoping to do at some point. Writing on February 2, 2007, Dr. Vicky Pope (head of the climate program at the UK Met Office Hadley Centre) provides an overview of the importance of climate models, and ends by writing that "in the long term, we would hope to have a climate model that could capture the observed regional detail and represent variations in weather systems (my emphasis)."
As Stephen Jay Gould wrote 'Central tendency is an abstraction, variation is the reality'As a footnote, the quote from Stephen Jay Gould (above) comes from p.48 of 'Life's Grandeur'. I strongly recommend chapter 4 for his description of how not to be misled by averages based on his cancer diagnosis at age 40. I have commented on the use of averages in market research in another blog.
January 19, 2010 - As a further footnote, James Hansen et al recently commented on the 2009 temperature record with the subtitle - "If it's that warm, how come it's so damned cold?" The paper describes how variable the weather can be compared to mean global temperatures, and draws specific reference to 'Arctic Oscillation':
'December 2009 was the most extreme negative Arctic Oscillation since the 1970s'
February 12, 2010 - A further footnote is that the Repower America campaign addressed a related point about increased snowfall in the North East of the USA. It speaks to extreme weather events rather than variation in temperature, so I am still wondering if we might expect some regions (specifically the UK, to answer John Redwood's question) to have some colder winter snaps in future. Anyway, here is what Repower America is saying:
Call it “Snowpocalypse” or “Snowageddon,” the mid-Atlantic and Northwestern U.S. have seen winter storms this year that rival anything in decades. Scientists agree that this kind of extreme weather is not just consistent with climate change research, it’s the direct result of rising temperatures in our oceans.
Arm yourself with facts and join Repower America in sharing the truth about climate change and extreme weather:
Fact: Climate change causes more frequent and severe snowstorms
Record snowstorms need two things: temperatures below freezing, and very high humidity. On a planet warmer by a few degrees on average, the Northeast US will still have plenty of days below freezing; the big difference will be warmer seas producing higher levels of moisture in the air — and therefore more severe cold-season storms.1,2
- Groisman et al. “Contemporary Changes of the Hydrological Cycle over the Contiguous United States: Trends Derived from In Situ Observations” Journal of Hydrometerology, (2004) http://ams.allenpress.com/archive/1525-7541/5/1/pdf/i1525-7541-5-1-64.pdf
- Changnon et al. “Temporal and Spatial Characteristics of Snowstorms in the Contiguous United States” Journal of Applied Metereology and Climatology, (August 2006), http://ams.allenpress.com/archive/1558-8432/45/8/pdf/i1558-8432-45-8-1141.pdf
February 13, 2010 - According to a letter in the New York Times, by Paul R. Epstein, it is the accumulated extra heat in the oceans that can cause 'bitter cold spells' ..
Two physical findings stand out. In the last 50 years the world ocean has accumulated 22 times as much heat as has the atmosphere (data provided by the National Oceanic and Atmospheric Administration of the Department of Commerce). It is this repository of heat — through processes like evaporation and ocean overturning — that drives the changes in weather we are experiencing: heavier precipitation events, sequences of large storms, bitter cold spells and prolonged droughts in some regions.
