Are You Ready? Building for Climate Change
By Mike Williams, Technical Director & Principal
Earlier in 2015, I attended Al Gore’s Climate Reality Leadership Corps Training. It was powerful. The most important takeaway for me was that changes in temperature can now be quantitatively tied to other changes in our climate. There really are more extreme weather events worldwide — floods, droughts, forest fires. And for some of them, there is a clear link to human-caused climate change.
For example, we’re seeing demonstrable increases in heavy precipitation days. A case in point: on July 8, 2013, a major storm dropped 12.6 cm of rain on Toronto — in two hours. I was trapped in that storm, and, honestly, it was scary. Sometimes climate change can seem pretty abstract, but with extreme events occurring more often, it’s starting to get personal. In the case of the Toronto storm, I took it very personally: It was my birthday!
And here’s where I’m starting to take a different view of climate change. At the training, a lot of the discussion centered on large-scale renewable energy applications. In my opinion it’s too late to focus solely on mitigating emissions. Real impacts are already happening. We have to start dealing with how this new reality affects our built environment. We urgently need to start designing for resiliency — for redundancy and passive options that can help keep people safer during extreme events and more comfortable every day.
To make buildings more sensitive to climate, I think the place to start is with what’s changing: the climate data. In the profession, we’ve maybe gotten too used to auto-selecting a climate data set. Let’s take a step back and ask the question: are we using the right climate data?
At RWDI we’ve worked on every continent and in every climate region; we’ve had to really look closely at our understanding of the data. Climate is so much more than temperature: it’s solar radiation, humidity, air pressure, precipitation, fog, visibility, wind speed and direction, and much more.
I want to challenge you to rethink climate data in two ways. First, do you really know what the climate is at your site? It sounds so simple, but I rarely hear anyone ask this question. Your building’s energy use will depend on the climate at its site, of course — but your best data may be accurate only for a site many kilometers away.
The following example really got us thinking. For an office building in Ontario we had two data sets available, one from 80 km north and the other from 80 km south. We ran our design with both data sets and found a few not-so-minor differences:
- 16% difference in heating loadings
- 10% difference in annual energy use for heating
- 4% difference in annual energy use
- 2 LEED EAc1 points gained/lost
This is why we’re working to develop some cutting-edge weather forecast models that can predict climate at a location in between two measurement stations.
Now the second rethink: are your averages right? Those weather files we’re using to run our energy models are based on a 25-year look-back: that is, on average weather data over the past 25 years. But we’re talking not just about climate, but about climate change. Are we correct in assuming that the next 25 years will be the same as the average of the last 25 years? Probably not.
So at RWDI we are also developing weather files that do a 25-year look-ahead based on worldwide scenarios developed by the Intergovernmental Panel on Climate Change (IPCC). We have to consider that the globe could warm by only 2 degrees or as much as 8 degrees. How does that change our decisions about a building we are designing today? This is still R&D, but very soon we'll be able to estimate energy use that will occur as a result of the different IPCC scenarios.
Coming back to the idea that a resilient building is one that one that helps keep people safe during an extreme event, I propose that we also need to re-imagine energy efficiency. Here in Canada one of our worst-case scenarios is extreme cold. So at RWDI we built an energy model of a typical residential tower during a power outage at –15°C. So, “Adios electricity!” What happens? For a building at a standard level of construction, that is, built to levels that are allowable by code today, the temperature dropped to below freezing within hours. Yes, hours. When we redid the model with better insulation values, lower window-to-wall ratios, better thermal mass, less infiltration — generally all the things you do to push energy performance — it took a couple days for the temperature to reach freezing. Bottom line: If you do the right things for mitigation, you’ll have both lower energy bills and a more resilient, safe design.
We took this idea of “and” in an interesting direction to address resident comfort in an entire community. To create a resilient built environment, we need to stop thinking of a building as a standalone entity but really think about how it plays within a community of buildings.
In this project we were retained to optimize the layout of a city with respect to how it interacts with its microclimate. Wind and exposure to the sun are the two main factors that affect human comfort at street level. We combined the results of separate wind and solar radiation models in a map of estimated thermal comfort for pedestrians. We presented our client with quite complex science that comes down to very binary, tangible decisions: green is comfortable, red is not, so let’s talk about how we can make the red areas more comfortable.
We’re using a similar approach when we design wind scoops that direct natural airflows to cool specific pedestrian areas or when we build an entire school with passive ventilation. Designs like these mean tangible comfort for people — even if there’s a heat wave or a power outage.
And that’s what resilient design must focus on: the extremely tangible, personal effects of climate change. What happens in my life and my neighborhood when 12 cm of rain falls in two hours on my birthday? What happens when the power goes out, the temperature is dropping, and my friend’s invalid grandmother lives on the 15th floor?
I think about that now, when I design a building. The impacts are already here.