Editor’s Note: Thank you to Editor James Fowler from Yolo County Master Gardeners (UCCE) for agreeing to share this article.

UCCE Master Gardeners in Yolo and Solano Counties are volunteer employees of the University of California. We can assist with community awareness regarding global temperature transitions affecting regional gardening. Additionally, we can offer conservation methods to support and restore biodiversity. Promoting species conservation, native plants, and regenerative gardening practices are part of the solution. Master Gardeners employ many climate-adaptive techniques that allow us to contribute insights and horticultural advice for impending climate changes.

Finally, we can follow UC Davis’s continuing research on adaptive methods to connect our local communities to practical advice for our changing climate to deliver information to our communities. For example, the UC ANR Strategic Initiatives Group has a local research plot with native Arizona trees that fit well in the Sacramento area increasing our resilience as temperatures rise. The trees were chosen for their ability to blend with our current climate and biodiversity profile. Interspersing them with our natives will assist with food and nesting sources as some of our current natives become less resilient.

How do Master Gardener’s support local habitat mitigation, restoration and adaption strategies?

This year’s incoming class of the UCCE Master Gardeners of Yolo County will be trained on climate change adaption techniques applied to home gardens. The class will survey useful traditional methods, along with new tools and technologies, emphasizing gardening with biodiversity and biome conservation practices in mind.

Two classes open to the public will follow in the Summer: “Beginning and Advanced Adaptive Garden Design and Construction.” The classes will address habitat restoration techniques for native plants and pollinators. UCCE Master Gardeners of Yolo County looks forward to encouraging climate change actions to achieve resilience and sustainability in Yolo and Solano counties.

Info on classes will be posted on the UCCE Master Gardeners of Yolo County Facebook account @yolomg.

Climate Change Data and Research Conclusions

Since the beginning of the Industrial Revolution, we have increased the amount of carbon dioxide (C02) from 300.0 ppm to 409.8 ppm. This is 121 billion Gigatons of carbon dioxide emitted into the Earth’s atmosphere by using fossil fuels in transport, manufacturing, and agriculture. More important is the increasing rate of emissions and temperature rise. Doubling C02 in the Earth’s atmosphere from the last ice age raised our global temperature enough to intensify the frequency and severity of weather events. The global temperature has risen by 1.5 ℃. Climate modeling indicates reaching 2 ℃ would move us from climate change to climate disruption. Climate disruption implies reaching tipping points from which all species including humans, would face mass extinctions.

Effect One – Global Warming

Figure 1 shows how average global temperature has increased relative to the 1951-1980 average temperature, since 1880. Though temperatures fluctuate naturally with atmospheric CO2 concentrations, since around the Industrial Revolution temperatures have increased much more quickly than at any time in the past. In the past century, average global temperature increased about ten times faster than it had during past transitions from ice ages to interglacials, or warmer periods between ice ages.

Figure 2 Increasing C02 and Global Temperature


Editor’s note: Visit the Cool Davis Basics webpage to learn more about carbon dioxide in the upper atmosphere. Our primary graph “shows atmospheric CO2 concentrations in parts per million (ppm) for the last 800,000 years. While it’s natural for CO2 concentrations to fluctuate over long periods of time, current concentrations are much higher than at any other time in the past 800,000 years. Atmospheric CO2 concentrations began increasing dramatically around the Industrial Revolution, when we started generating large quantities of CO2 as a result of burning fossil fuels.”

The current CO2 ppm is reported with every Cool Davis newsletter. The reading as of May 3, 2021 was 419.41 CO2 ppm. For daily updates of the CO2 concentration at Mauna Loa Obervatory, Hawaii, see keelingcurve.ucsd.edu.

Effect Two – Loss of Biodiversity

Increased global warming hastens the loss of biodiversity. The term biodiversity refers to life on Earth from genes to ecosystems. It encompasses the evolutionary, ecological, and cultural processes that sustain life. The most severe losses have been identified as biodiversity hotspots. The criterion to identify geographical hotspots are:

  1. The biome must have at least 1500 endemic plants (vascular plants found nowhere else in the world).
  2. The biome must have 30% or less of its original natural vegetation.

The International Union for Conservation of Nature (ICUN) has identified thirty-four hotspots around the world. If left unchecked, the combination of global warming and species extinction will result in massive desertification, food scarcity, and mass migration from uninhabitable areas in the world. California is a designated biodiversity hotspot.

NASA Climate Change – Mitigation, Restoration, Adaption

Currently, three main strategies are being developed to prevent climate disruption.

  1. Mitigation by reducing global carbon emissions to zero within the next twenty to thirty years.
  2. Draw Down of C02 which persists for hundreds of thousands of years in the atmosphere without intervention.
  3. Adaption through conservation and restoration of species habitats based on temperature changes within regional biomes.

U.C. Davis – California Climate Predictions and Adaptive Strategies

The university’s research on climate change is specific to the Sacramento Valley. U.C. Davis has this mission: “Sustainability”. While many processes are global, solutions can be applied in local communities and scaled up to the state and national level. UCD is researching ways to adapt to impending climate changes through mitigation and conservation practices specific to the Sacramento Valley. Two degrees Celsius may seem like a few degrees we could tolerate. But global warming is not local weather. UCD has a website devoted to the topic of sustainability and climate change.

This website discusses future changes and solutions to global warming that apply to the Sacramento area: https://climatechange.ucdavis.edu/news/becoming-arizona/. U.C. Davis researchers know our future temperature profile will be like Arizona’s climate today. The university is in touch with Phoenix and Tucson to research adaptability in terms of plants and animals. UCD’s website lists solutions any citizen can utilize: https://climatechange.ucdavis.edu/solutions/.

Recent California wildfires hint at a climate disruptive future if we do not accelerate plans for mitigation, drawdown, and adaption. Are you thinking that California’s climate is disruptive already? Certainly, California foreshadows unpredictable weather calamities. However, climate disruption forecasts more severe ecological events. Think of climate disruption in the same way you think of COVID-19. It is a global disruptive influence, from a known biological process (influenza), that is unpredictable.

Some climate disruptions are more severe than others. Scientists who study climate disruption are modeling for temperature tipping points within biomes. The Intergovernmental Panel on Climate Change’s fifth climate assessment, AR5, defines a tipping point as “an irreversible change in the climate system”. A climate model at the Woodwell Climate Research Center, Northern Arizona University, identified critical temperature tipping points beyond which plant’s ability to capture and store atmospheric carbon dwindles. Such a process reversal would inhibit soil carbon sequestration.

Currently, photosynthesis acts as a carbon sink, drawing off some of the C02 we place in the atmosphere. The Woodwell Climate researchers noticed, in nearly every biome across the globe, there is a temperature maximum at which carbon uptake declines while carbon dioxide released back into the atmosphere accelerates. Looking at the current rate of global warming, they believe a photosynthetic maximum temperature may be reached within twenty to thirty years.

By Deborah Sorrill, UCCE Yolo County Master Gardener

Thanks to Jim Fowler for permission to use UCCE Master Gardeners of Yolo County content and images.

Visit the Yolo County Master Gardener website


Read the full Spring newsletter


Full list of this spring’s articles:

“The Gardening-Nurturing Connection” – Sharon Schwarz

“Building a Community Treasure: How UCCE Master Gardeners Helped Create an All-Volunteer Public Garden” – Ann Daniel and Peg Smith

“Doggone It! Common Landscape Plants Toxic to Dogs” – Michelle Haunold Lorenz

“It’s Easy to Grow Citrus in Containers” – Michael Kluk

“Invite Songbirds to Your Yard with Native Plants” – Tanya Kucak

“Change in Leadership at Grace Garden” – Cid Barcellos

“Adapt Your Garden to Climate Change” – Deborah Sorrill

“Passalong Plants” – Sue Fitz

“Spring Garden Tips 2021’ – Peg Smith

“UCCE Master Gardener, Yolo County, Plant Sale”