Climate Change Update

State of the Science and Moments of Hope

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E. Jamie Trammell – Environmental Science, Policy, & Sustainability Southern Oregon University

Presentation Outline

• Intro and Story
• Updated Anticipated Impacts
• How we are/expect to experience climate change
• Expected impacts by region
• Attribution Science
• What is it, how does it work, what is it telling us now?
• This year’s El Niño
• Scenario planning, best interventions
• We just dropped RCP 8.5
• Is that a good thing or a bad thing?

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Why do I do this work?

• Lifelong United Methodist
• Grew up in Littleton, CO
• Member of the Choctaw and Chickasaw Nations
• Grandfather grew up on reservation, great Aunt still has her 100-acre “Indian Land”
• Have always had a deep environmental ethic
• Eternal optimist, always looking for a better understanding of how things could work

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Current Understanding of Impacts

Where and how do we expect climate change to become noticeable?

Current Impacts�Average Annual Temperature

https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/

Current Impacts�Average Temp in January

https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/

Future Impacts�Days over 95˚F

https://crt-climate-explorer.nemac.org/

Future Impacts�Days over 105˚F

https://crt-climate-explorer.nemac.org/

Future Impacts�Minimum Temp < 32˚F

https://crt-climate-explorer.nemac.org/

Future Impacts�Minimum Temp < 32˚F

https://crt-climate-explorer.nemac.org/

Future Impacts�Growing Degree Days

https://crt-climate-explorer.nemac.org/

Attribution Studies

How do we know if what we are experiencing is related to long-term climate change?

Attribution Studies�Basics

• How much more likely did climate change make this event?

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• How much more intense did climate change make this event?

Attribution Studies�Basics

Andrew Dessler

Texas A&M

@theclimatebrink

Attribution Studies�Highlights

• Hurricane Harvey dumped over 50 inches of rain on southeastern Texas, was determined to be 15% to 38% more intense and roughly three times more likely.
• Mann et al. 2017 Scientific Reports, 7: 45242. DOI: 10.1038/srep45242
• The June 2021 "heat dome" in the PNW shattered historical records by up to 5°C (9°F) in some areas was "virtually impossible" without human-caused climate change.
• Philip et al. 2022 Earth Syst. Dynam., 13. DOI: 10.5194/esd-13-1689-2022
• The increase in extreme fire weather bears a clear externally forced signal, detectable at 99% confidence above natural variability and attributable to human-induced climate change.”
• Turco et al. 2026 Science Advances 12(11). DOI: 10.1126/sciadv.adx9845

What about El Niño?

El Niño�Possible “Super”

El Niño (or Anticipated Future Climates)�Analogous Climates

El Niño (or Anticipated Future Climates)�Analogous Climates

MATT FITZPATRICK/UNIVERSITY OF MARYLAND CENTER FOR ENVIRONMENTAL SCIENCE

Promising Scenarios

Scenarios�The C Cycle

Scenarios�Project Drawdown

Scenarios�Project Drawdown

Scenarios�Nature-Positive

• Think creatively about the complexity
• Work closely with people
• Define positive futures

Scenarios�Impact of Policies

Zeke Hausfather

The Climate Brink

Is the RCP 8.5 really gone?

And what does that mean?

Scenarios

“Scenarios … define plausible alternative descriptions of how the future may develop based on a coherent set of assumptions, they are used by different research communities to explore potential future avenues of socio-economic conditions, assess the effects of different drivers of climate change, characterize future climatic conditions, and assess impacts of climate change as well as adaptation and mitigation responses. As such, scenarios are also useful to bridge across different research communities.” van Vuuren et al. 2026 https://doi.org/10.5194/gmd-19-2627-2026

Representative Concentration Pathways (RCPs)�Emission Scenarios

Trends in concentrations of greenhouse gases. Grey area indicates the 98th and 90th percentiles (light/dark grey)

From van Vuuren et al, 2011, 109

RCP 8.5�RIP

Hausfather and Peters, 2020, Nature, 577

Take Home�There is Hope

• If the worst case scenario is not really feasible
• That gives us hope
• If we can imagine scenarios that are nature-positive
• That gives us hope
• If we can continue to attribute events to climate change
• We can use those same models to identify regional impacts
• If we can continue to have conversations like this
• That gives us hope

Thank you!!

E. Jamie Trammell

Professor and Chair of Environmental Science, Policy, & Sustainability

trammelle@sou.edu