In 2024, Colorado State University’s Colorado Climate Center published the third edition of its Climate Change in Colorado report (Bolinger et al., 2024) that discusses recent trends and model-based predictions of the climate and hydrology in Colorado. This report claims that “the evidence that human influences have impacted the global climate system has only strengthened.”

Are Colorado and its citizens being negatively impacted by human-driven climate change?

The objective of our report is to compile and analyze scientific data to answer this question. To meet this objective, we gathered data from various sources, including government agencies, universities, and peer-reviewed papers.

Based on these scientific data, the key findings of our study are as follows:

Temperature: Temperatures in Colorado have fluctuated since the late 1800s, alternating between periods of warming and cooling. Since the mid-1970s, Colorado’s annual average temperature saw a modest increase, with temperatures during the 2020s comparable to those from past decades and from the late 1800s to the early 1900s, which indicates that Colorado is not warming dangerously. This modest warming can be attributed to the prominent increase in the annual average minimum temperatures during this time, as recent values of the annual average maximum temperatures are comparable to those from past decades and from the late 1800s to the early 1900s, despite its increase since the 1990s. In other words, the annual average temperature in Colorado is increasing because the cold temperatures are becoming less cold, and not because hot temperatures are becoming hotter.

Heat waves and cold waves: The number of hot days in Colorado with temperatures at or above 95 °F (35 °C) has been decreasing since its peak in the 1930s, which means that heat waves are not becoming more frequent in Colorado. Similarly, since its peak in the 1920s, the number of cold days in Colorado with temperatures of or below 0 °F (-17.8 °C) has been decreasing, which means that cold waves are not becoming more frequent. This development is beneficial for people, as there are significantly more deaths from cold than heat, as well as for agriculture, as warming extends the length of growing seasons, allowing for more plantings. Despite the modest warming, Colorado has experienced a slight increase in snowfall.

Precipitation and drought: The annual precipitation in Colorado is dynamic, with significant fluctuations year-to-year, but overall, the annual precipitation in Colorado shows no indication of a decreasing trend, as recent values are comparable to those from past decades. Therefore, Colorado is in no danger of a precipitation-driven drought. Since 1895, Colorado has been alternating between dry and wet periods. Dry periods since 1999 can be partially explained by natural phenomena in the Pacific Ocean, namely El Niño and La Niña.

Natural disasters: Wildfires, tornadoes, and winter storms are not becoming more frequent or severe. Except for a couple of unusual years, overall flood data do not indicate that these events are becoming more frequent or severe.

Air Quality: Air quality in Colorado has improved significantly over the years, with the concentrations of six of the seven criteria air pollutants below the limits specified by the National Ambient Air Quality Standards (NAAQS). In the case of ozone, its concentration is near the limit specified by NAAQS, which means that its concentration is not dangerously high.

Agriculture: Crop productivity is increasing in Colorado and globally due to agricultural innovation, increased carbon dioxide fertilization, longer growing seasons, CO₂-related increased drought resistance, and the use of fossil fuel-based fertilizers and pesticides.

Carbon dioxide: Carbon dioxide (CO₂) is an essential and beneficial gas for life on Earth, as plants cannot produce oxygen and food without it. Exposing plants to increasing CO₂ concentrations allows them to grow taller, produce more food, and better resist drought. CO₂ also contributes 70% to the greening of Earth, as confirmed by NASA. Colorado has enjoyed the benefits of CO₂, with its increasing yield of various crops. Finally, because the radiative forcing that causes greenhouse gas warming is nearly saturated with CO₂ at current concentrations, the warming effect of each newly added CO₂ molecule to the atmosphere is small.

Conclusions: Based on the scientific evidence presented in this report, there is no climate crisis in Colorado. Moreover, CO₂ is essential and beneficial for life on Earth. Therefore, policies to reduce CO₂ emissions are ecologically and economically destructive.

Download the complete report here:

Colorado and Climate Change Final Digital-compressed