Written by Barbara Hilton

What is the Sixth Assessment IPCC Report and what does it say?

Human activity is an indisputable, direct cause of climate change, change that over the last seventy years is unprecedented. According to the most recent assessment of the IPCC, the Intergovernmental Panel on Climate Change, released in August 2021, the rapid change in climate and environment is anthropogenic. This comes less than a decade after the release of the IPCC’s Fifth Assessment Report (AR5) in 2014. This Sixth Assessment Report (AR6) both expands on the previous reports findings and introduces new information after advancements in methodology, technology, new understanding in attribution, and new studies.

The report is the first of four parts: Working Group I, Working Group II, Working Group III, and the Synthesis Report. This portion is the contribution of Working Group I, which discusses the physical evidence and observations in support of recent environmental and climate change; called Climate Change 2021: The Physical Basis. The report and report factsheet state that this portion of the assessment combines “evidence from paleoclimate, observations, process understanding, global and regional climate simulations,” in order to give an accurate view of how the state of the climate came to be and why it is evaluated at the extreme it is now. While Working Group I does not explicitly discuss the impact of the climate or sustainability and mitigation, it does integrate the findings of each Working Group, so some information on impacts and mitigation will be found in this portion.

What does the IPCC Report say about Colorado?

Various North American and Colorado specific assessments are mentioned in this report. Specifically, the impact of climate change on the Colorado River basin area in regard to drought, lowered precipitation, and increasing temperatures in the southwest are mentioned. Western Colorado is within the river basin and parts of eastern Colorado receive water from the river. It helps to supply water for municipal use, agriculture, power, holds cultural significance, and provides a home to many species; both humans and animals across the southwestern United States and northwestern portion of Mexico rely on the Colorado River. While the conclusions reached about the consistency and extent of hydrological drought in the western portion of the United States varies, evidence suggests that within the Colorado basin area, rising temperatures are causing an increase in hydrological deficits. Hydrological drought is a type of drought that occurs over many years and is measured in a variety of ways, such as soil moisture or runoff. While other types of droughts (agricultural and meteorological) are usually immediately apparent and are definitely increasing (“high confidence”). As global temperature rises, it is projected that regions that rely on snowpack would be significantly more affected than those that do not, (“medium confidence”).  

While it is true that temperatures are increasing across the globe and the United States, there is not much agreement that the types of observed changes are hot extremes in central and eastern North America. In these regions, precipitation increased and whether or not drought has changed is not yet agreed upon. These findings may be surprising to most due to common understanding in regard to climate change and its effect in the United States; Colorado and the western portion of the States juxtaposed these findings, following anticipated trends, however. There is “high confidence” that increasing temperatures due to human influence is a direct cause of the extension of the wildfire season, increased drought, and decreased precipitation in the southwest United States. This year was the 51st driest year in the last 127 years for Colorado, according to the National Integrated Drought Information System. While drought naturally occurs in Colorado’s climate system, its increase in severity is of human influence. Precipitation has also decreased overall, although Colorado’s snowpack levels this season are doing well now, which exacerbates drought and directly affects Colorado economy and wildlife over the long term.

So, what does the IPCC report really mean for Colorado? The nearly 3,500-page report details studies done around the globe for a variety of observations and attributions; it only briefly addresses Colorado specific regions. The studies that do mention Colorado present information that seems to be common knowledge as far as Colorado becoming drier and hotter. What this report actually tells us is that Colorado is being affected differently than other parts of the United States and hotter, drier conditions mean more wildfires and insect epidemics destroying forests, more frequent heatwaves that last longer, and a threat to water availability across the state. From the time that our trees bloom, to the snow that covers our mountains and plains, to the animals whose lives are dependent on the health and stability of our particular ecosystem, everything that makes Colorado great is in jeopardy.

What can Coloradans do?

The IPCC will release the contributions of Working Group II and Working Group III in February and March of 2022. These reports will address what the exact impacts of climate change has had on ecosystems, biodiversity, and regional conditions and ways in which further climate change can be lessened. In the meantime, what can Coloradans do? Join local organizations that share in your concern about climate change, such as 350 Colorado, attend town halls and meet with your representatives, stay informed about what policies, companies, and initiatives are helping and those that are harming Colorado’s and the nation’s climate are doing, and, most importantly, stay determined. Protecting Colorado, mitigating future climate change, and reversing the effects on the environment cannot be done through one bill, action, protest, etc. Just as the impacts of climate change have been relentless, so must the actions to defend against it.