Hot day in Vermont

Posted by on Nov 7, 2015

Global temperatures, September 2015. Graphic: NOAA National Centers for Environmental Information

Global temperatures for September 2015, blending land and ocean data. Source: NOAA National Centers for Environmental Information

When I was out for a walk yesterday afternoon—comfortable in shirtsleeves with the November 6th temperature in Dummerston, Vermont rising to over 75°F—my mind turned to global warming. I was reminded of a news report some weeks earlier that 2015 would almost certainly break a temperature record globally.

I was curious about that, so went online last night. How could climate scientists be so confident in predicting that 2015 would be the warmest year on record, since we were only three-quarters through the year? What I found was both surprising and frightening.

The hottest years, month-by-month

The chart below is from the NOAA National Centers for Environmental Information (NCEI) website. On it are shown the six hottest years on record, globally—by month—along with the average temperatures for 2015, through September. The six warmest years in the chart, in order, are 1998, 2009, 2005, 2013, 2010, and 2014 (the current record-holder). Those lines are in color, while 2015 is the black line.

Monthly average global temperatures for the six hottest years on record (color graphs) and data for 2015. Source: NOAA National Centers for Environmental Information

Monthly average global temperatures for the six hottest years on record (color graphs) and data for 2015 (black graph). Source: NOAA National Centers for Environmental Information

What is remarkable is that for every month this year, the average global temperature is well above the monthly temperature for those six-hottest years. It is striking just how much hotter 2015 is than those other six years. It’s easy to see how scientists could so confidently conclude that the annual average global temperature for 2015 will be a record.

Monthly deviations from the 1880-2015 average

I looked further on the NCEI website and came across another chart showing the top-ten months with the greatest departures in average global temperature, compared with the average for the period from 1880 to 2015. This chart is shown below. These anomalies range from 1.51°F to 1.62°F.

Individual months from 1880 to 2015 in which the average global temperature exceeded the long-term average by the greatest amount. Source: NOAA National Centers for Environmental Information

Individual months from 1880 to 2015 in which the average global temperature exceeded the long-term average by the greatest amount. Source: NOAA National Centers for Environmental Information

What is so striking in this chart is that of those ten months with the largest deviation from the long-term average, six of those months have occurred in 2015. Think about that. This data set includes global average monthly temperatures for 1,629 months, and of those six were this year—with three months still to go.

Will we call it global warming again?

Given the politics in the U.S., there has been a trend away from referring to “global warming.” We have opted to refer to “climate change” instead. This shift was made, I suspect, because every time there’s a cold spell climate change deniers would rush to the media claiming that global warming wasn’t happening.

Climate scientists argued, as they always have, that there is a lot of variation in temperatures and that, in fact, the climate models predict that changes in the global jet streams and ocean currents were expected to result in cooling in some places in some years. That could better be conveyed to a lay audience—especially one in which a significant percentage, as far as I can tell, doesn’t believe in dinosaurs—if the scientists referred to climate change rather than global warming.

But the global data emerging from 2015 makes me wonder if we will again begin referring to global warming.

The relevance to resilience

What all this tells me is that those of us focused on resilient design will have to ramp up our efforts to address heat waves and strategies for keeping people safe during summer months if disturbances—storms, tornadoes, wildfires, and such—cause power outages that prevent us from using air conditioning.

We have a lot of work to do!

#     #     #     #     #

Along with founding the Resilient Design Institute in 2012, Alex is founder of BuildingGreen, Inc. To keep up with his latest articles and musings, you can sign up for his Twitter feed. To receive e-mail notices of new blogs, sign up at the top of the page.


  1. Alex,

    The situation described in this post is alarming.

    I’d like to echo the sentiment that passive cooling (and heating) measures are maximized in new and retrofit projects to both create resilient structures during system failures, and to take advantage of the long term benefits of insulation, air sealing, and especially shading. While I understand that active cooling is becoming more accessible and less expensive, it’s important to plan for “full spectrum” use of the building enclosure. Value engineering exterior shading out of a project due to the availability of lower cost active cooling will leave many large building occupants exposed to risk. Even a short term outage in a poorly shaded high-rise multifamily project such as I see going up regularly in urban centers can become uninhabitable after a few days with no active mechanical systems.

    • Albert, agreed. Though I might take issue with your comment that a high-rise multifamily building may become uninhabitable after “a few days”… In New York City in July, such a building—if overglazed as most are today—could become uninhabitable after just a few hours after power is lost. So, I think your point is even more important.

  2. Alex:
    sorry to hear about your unseasonable weather (we had same problem in N CA too). It looks like the NE region of US is in for a significant shift toward warmer and wetter climate by 2040 or so
    (Thibeault & Seth, 2014,;
    Ning et al. 2015,

    This strongly supports the need to factor in regional climate change in life cycle analyses for building design & operation.

    And thanks for reminding folks to look at the data, and to plan and act accordingly.

    For recent trends in max WBGT , which also considers humidity, wind, etc., see info for your location at – For Brattleboro VT in August, max WBGT has been increasing 0.14 F/decade since 1980, but ranges from 68 to 73.5 F.

    re: the NOAA temperature records and predicting the annual avg., you did not quite answer your question. I think the answer is in the statistics & probabilities — I suspect that NOAA looked at historical data & estimated the probabilities for the remainder of the year, and concluded it would be very very low chance that we would have a Fall cold enough to counterbalance the preceding hot 9 months.

    re: terminology, climate change seems too ambiguous and innocuous to me. Someone (James Hansen?) has suggested “Wilding of the Weather” instead, to reflect the increase in all sorts of extreme weather — I like it but it has not really caught on.

    I tend to prefer “global warming”, and even “global baking, steaming, roasting” etc., because increased heat stress is expected to directly and indirectly harm human health & perhaps ecosystems the most among weather events, and the connotation is for something not good in general. And because warming is something we can easily sense or perceive ourselves. Even Natl. Geo’s cover in the latest issue has “Cool It” on the cover for the special issue on climate change (, Nov 2015 issue.

    Meanwhile, in California, an unusual algae bloom has postponed the Dungeness crab season and killed seals, and shifts in ocean temperature have led to big die offs of several other species from lack of food/prey.

  3. just heard a new term that connotes some health hazard: “Cli-mydia”
    (from Eric Corey Freed at Living Bldg. Challenge, on Voice of America of all places:


Get every new post delivered to your Inbox

Join other followers