Climate Change in Boulder County (1985–2022)
Climate change has been a ‘hot’ topic in recent history, or specifically the current time period called the Anthropocene. The Anthropocene is the current geological period of time which is described by the influence of humans (hence “anthro”) on the natural environment. Due to climate change all over the world, we are experiencing new changes to weather patterns, such as more extreme weather events, more record breaking temperatures (both extreme highs and lows), different precipitation and snowfall rates, and other shifts in Earth’s weather patterns. Looking at weather trends over time can give us some indication of how Earth’s climate is changing, because climate is the long term trends of how the atmosphere is changing.
Climate change not only affects weather patterns, but it has implications for how we live our daily lives and the quality of life in the future. Climate change effects include sea level rise, more intense droughts, less available drinking water, decreased air quality, changes in crop yields, biodiversity loss, increased frequency of forest fires, and a slew of other environmental and societal consequences. This is an issue that has gained traction in the news with climate strike events and activists speaking out against the issue and its impacts on the environment and society. In 2019, there was a series of international climate strikes which overwhelming demanded something should be done about global climate change. Environmental activists such as Greta Thunberg who has recently emerged as a figurehead of the younger generations’ involvement in climate change movements and efforts. There are also many organizations and movements that have climate change initiatives, such as the Climate Action Network International, Peoples Climate Movement, Citizens’ Climate Lobby, and Environmental Defense Fund.
Boulder County has had many extreme environmental and weather events occur, most of which can be attributed to climate change. Some of these climate change effects on Boulder County include increased risk of more intense wildfires, reduced snowpack, earlier in the season snowmelt, higher daily temperatures, extreme weather events, more precipitation in the form of rain rather than snow, and increased frequency and intensity of flooding events. These climate change effects also have implications for human health and quality of life. You can learn more about these climate change impacts specific to Boulder County here.
Personally, after being at the University of Colorado, Boulder for the past four years of my undergraduate experience, I have witnessed numerous extreme weather events, wildfires, extremely poor air quality (due to wildfires) and extreme high daily temperatures. Being a student here in the Geography and Environmental Studies departments, I developed a lot of my own research related to climate change and ocean acidification (climate change’s evil twin). In classes and talking with other students I learned about the 2013 Boulder flood event and how this event impacted locals. This devastating flooding event also could be attributed to climate change, as intense floods (and persistent droughts too) are effects of climate change. Having these experiences and being told about past weather events, I wanted to explore past weather patterns in Boulder County.
To dig into this phenomenon further, I decided to investigate trends in weather data spanning from 1985 to 2022 for Boulder County. The research question that is guiding this analysis is: how has Boulder County experienced climate change through changes in annual air temperature, precipitation, and snowfall data from 1985 to 2022? The annual data for air temperature, precipitation, and snowfall were obtained from the National Oceanic and Atmospheric Administration’s (NOAA) National Centers for Environmental Information (NCEI). One constraint of this data set is that the farthest back the data goes is 1985. However, over the span of 37 years there are still some interesting trends to extract. The data was collected from weather stations spatially situated in Boulder County. To get singular values for each year, I averaged the weather data measurements of all the weather stations for each year. Aggregating the weather station data together allowed me to pull out some interesting trends for Boulder County’s weather data.
For the first part of this analysis, I used the annual total precipitation data and averaged it over the weather monitoring stations data. I created a simple bar plot to visualize the trends, and it appears to be negatively correlated. To investigate this observation further, I calculated the correlation coefficient, and found that it was -0.40, which is a significant enough correlation. This preliminary observation can indicate that over time, Boulder County’s mean total precipitation rates have generally decreased since 1985.
After looking at the precipitation data for Boulder County, I wanted to see if there were any similar or different trends in snowfall data. Once again, I used the average annual snowfall data and averaged those values across the weather data stations for each year. I made another bar plot to visualize the snowfall data over time, and wanted to further examine the correlation. I calculated the correlation coefficient as -0.05, which is not nearly as strong as the previous precipitation data. This result could mean that Boulder County’s snowfall has widely varied since 1985, with no significant trend (potentially a small negative correlation, but not very strong).
As for the air temperature of Boulder County, I used a similar technique of averaging the weather station’s average yearly air temperatures. The line chart for the average temperature since 1985 shows a pretty strong negative correlation. I tested the actual correlation, and found that it was -0.45, which is slightly stronger than the correlation coefficient for average total annual precipitation. I know that this decrease in temperature may seem a bit counterintuitive, as you may think that it would be getting hotter. Do keep in mind that this is an average value, so you can’t see the very high values within the year, which leads me to my next set of variables that I set out to analyze, the average annual temperature maximum and minimum.
The average annual temperature maximum and minimums show very similar trends when plotted together on a line plot. Both of the data sets show an uptick in 1985, a dip in 1990, another uptick in ~1995, then finally the both tend to level out for the rest of the graph.
I measured the correlations for each data set; the temperature maximum had a stronger correlation of -0.49, while the temperature minimum had a weaker correlation of -0.16. The negative correlation of -0.16 for average minimum temperatures indicates that there have been more extreme colder temperatures since 1985. Conversely, there are less extreme average warm temperatures for Boulder County since 1985. I also wanted to explore how the data for average extreme temperatures are distributed by creating histograms shown below. They both tend to show a similar right skew in the data, meaning that the majority of the observations of extreme temperatures are lower. This result makes sense, given the correlation data because there were more extreme colder temperatures, and more less extreme warmer temperatures.
As for what these results mean for changes in weather patterns for Boulder County, the mean total annual precipitation rates have generally decreased since 1985, meaning that the environment is becoming dryer. If the environment is becoming drier, it is much more likely for wildfire events to occur, which we have seen an uptick in their frequency and intensity recently. The snowfall data indicated no significant change, but it could be on average decreasingly ever so slightly since 1985. The air temperatures for Boulder County on average are also decreasing, however, the more interesting story here is the average annual temperature maximums and minimums. In general, Boulder County is experiencing less extreme average annual high temperatures, but is experiencing more extreme average annual low temperatures.
Boulder County has also acknowledged that climate change is something that current and future residents are already facing. In 2022, the Boulder County’s Office of Sustainability, Climate Action & Resilience launched a Climate Innovation Fund of $450,000 which supports local projects that aim to remove carbon dioxide and promote landscape restoration. Susie Strife, the Boulder County Director of Sustainability, Climate Action & Resilience stated “The climate crisis is already impacting everyday life in Boulder County in the form of year-round wildfire seasons, poor air quality, and more days of extreme heat. We need to continue to invest in rapid emissions reductions and the critical counterpart of restoring our atmosphere through carbon dioxide removal if we are serious about supporting the solutions needed to meet our climate goals.”
Initiatives such as these taken on by Boulder County are what is needed to create a more sustainable future, as anthropogenic carbon dioxide emissions are occurring at unprecedented rates. Local means of mitigation and adaptation to climate change are just (and if not more) as important than international treaties, like the Paris Agreement. International treaties are tricky to come to effective fruition because they take a long time to develop and are dependent on many factors and actors. Local governments can aid in providing climate solutions tailored to their environment and residents’ needs. In addition, collaboration and communication with residents is always an effective means to make this process more fair, and the addition of local knowledge of residents can aid in creating more effective climate solutions. There is no one size fits all solution to mitigation or adapting to climate change, but taking these initial steps to funding projects that could decarbonize the atmosphere is a great step in the right direction.