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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 07/09/2026

Happy have played a small role in preparing Canada's Changing Climate Report 2026 Ch3: Overview of Future Changes in Climate. Check it out here

canada.ca

Canada’s Changing Climate Report 2026 - Canada.ca

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Reposted by Mitchell Dickau, PhD

Dr. Aaron Thierry @thierryaaron.bsky.social · 13/08/2026

"For highly irreversible #climate variables like permafrost and ocean changes, we show that the outcome of overshoot is linearly related to the time-integrated overshoot magnitude, which we define here as the degree-years of temperature overshoot." www.nature.com/articles/s43...

nature.com

Irreversible climate changes driven by degree-years of temperature overshoot - Communications Earth & Environment

Degree-years of temperature overshoot, which represent the time-integrated overshoot magnitude, are proportional to the outcome of overshoot in some slow-responding climate variables, revealed by...

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 17/08/2026

Happy it’ll be useful :)! The real thanks should go to Andrew though, he did all the heavy lifting

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 17/08/2026

Thanks to @andrewdessler.com for making his code repo public. All credit for the analysis goes to him.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 17/08/2026

Andrew's code takes satellite data from NASA's MODIS Multi-Angle Implementation of Atmospheric Correction (MAIAC) product (MCD19A2) and looks at all days that are identified as smoke. So these figures just show smokey days but no information about the intensity of smoke.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 17/08/2026

In 2023, the record wildfire year, 36.32% of grid cells in Canada saw a month or more smoky days.

This figure shows maps of Canada for each year from 2000 to 2023 showing the number of smoky days at each grid cell.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 17/08/2026

The analysis shows that, comparing 2001-2005 to 2021-2025, 83% of Canada has seen an increase in smoky days. The average increase in smoky days between these two periods was +5.3 days and a large portion of central Canada has seen +10 smokey days.

This figure shows the change in smoky day frequency over Canada.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 17/08/2026

How have the number of smoky days in Canada changed in the past decades? Inspired by @andrewdessler.com's blog post, I decided to adapt Andrew's code and run the same analysis for Canada.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 30/07/2026

Reading: 2.0°C allowable emissions – doi.org/10.5194/essd... Post net-zero temperature change – doi.org/10.5194/bg-1..., doi.org/10.1038/s415... Future warming uncertainty – doi.org/10.5194/esd-... Current policy warming trajectory – climateactiontracker.org/global/cat-t...

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 30/07/2026

It's true that we are not currently on track. Current policy suggests we are not on track for ~2.6 °C by 2100. However, it's important to not lose site of the fact that the MAIN uncertainty in how much future warming occurs is OUR FUTURE EMISSIONS. We cannot lose sight of the agency we have.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 30/07/2026

Translation – we still have allowable emissions while we transition away from fossil fuels. This means we can still limit warming to below 2.0°C if there is political will to shift away from fossil fuels and bring our CO2 emissions to zero (or near zero) in the next ~20-40 years.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 30/07/2026

However, the best science tells us that: 1) to have a 50% chance of limiting warming to 2.0°C, we can emit 1050 Gt CO2 (2300-600 Gt CO2 10-90%) – for reference, we emit about 40 Gt CO2 per year globally 2) once emissions reach zero, we don't expect much temperature change in either direction

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 30/07/2026

Limiting warming to 2.0°C is not out of reach!! The current long term trend has us at about 1.4°C of warming, and we've had individual years above 1.5°C of warming. This means that the 1.5°C target is now out of reach given it would be next to impossible to reduce our emissions to zero over night.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 30/07/2026

Listened to @dwallacewells.bsky.social on The Gray Area @vox.com (megaphone.link/VMP9497961815). I'm a fan of David's work. But I noticed he says that 2.0°C is out of reach. Perhaps he misspoke – he's normally very well informed. As a climate scientist I'd like to correct the record.

megaphone.link

The “Godzilla El Niño” is coming by The Gray Area with Sean Illing

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 29/06/2026

These results also imply that, because these slow-responding climate changes are path dependent, using global warming levels to communicate climate changes may underestimate changes for slow-responding variables in the event that future temperature peaks-and-declines.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 29/06/2026

So, a sharp overshoot likely causes less permanent planetary damage to slow-responding systems than a lower-temperature overshoot that drags on for decades.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 29/06/2026

These results imply that the additional effects caused by overshoot for some slow-responding Earth processes are dictated by both the magnitude and duration of overshoot.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 29/06/2026

We find that the additional change in overshoot scenarios relative to baseline scenarios is proportional to the magnitude x duration of overshoot, which is known as the degree-years of overshoot. Interestingly, this proportionality is independent of peak temperature.

A figure showing the relationship between degree-years of overshot (x-axis) and the additional ocean warming caused by overshoot (y-axis). Dozens of faint grey trajectory lines loop upward and to the right, tracing the evolution of this relationship over time in an ensemble of overshoot scenarios. The endpoints of all these trajectories generally land on a single, linear red regression line that extends from the origin, annotated with an R-squared value of 0.996. A horizontal colorbar at the bottom indicates the "Peak temperature reached during overshoot (°C)," ranging from blue (lower peak temperatures) to red (higher peak temperatures). The endpoint dots fall perfectly along the same straight line regardless of their colour, visually demonstrating that long-term additional ocean warming is proportional to the cumulative degree-years of overshoot and independent of the peak temperature reached.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 29/06/2026

By comparing scenario pairs, we also identify variables that exhibit short-term irreversibility immediately following overshoot. Some of these variables include the permafrost carbon pool, meridional overturning (AMOC), thermosteric sea-level-rise, ocean temperature, and ocean oxygen.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 29/06/2026

We find that immediately following overshoot, the high-latitudes are warmer while equatorial and mid-latitudes are cooler in overshoot scenarios relative to their respective baselines. Illustrative here by the average reversibility (%) of SAT at each grid cell across the ensemble.

A global map illustrating the average spatial reversibility percentage of Surface Air Temperature (SAT) across a climate model ensemble immediately following a temperature overshoot. A vertical colorbar on the right scales from 80.0% (dark red) to 120.0% (dark blue), with 100.0% represented as white. The map shows a stark regional contrast: high-latitude regions, including the Arctic and Antarctica, are shaded in deep red and orange (below 100%), indicating they remain warmer than the baseline scenario. Meanwhile, low- and mid-latitude regions across the continents and oceans are shaded in light to dark blue (above 100%), indicating they are cooler than the baseline. Black contour lines outline the boundaries between these warming and cooling zones.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 29/06/2026

Removing CO2 at scale may not be physically, economically, or socially feasibly, but there is still value to understanding overshoot. So what are the implications of overshoot? We simulated 42 pairs of overshoot vs. baseline scenarios in a intermediate complexity climate model to find out.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 29/06/2026

We are off track to limit warming to 1.5–2°C. So if we are to meet the Paris goals, this means it will likely occur after overshooting limits first, then removing CO2 from the atmosphere to lower temperature.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 10/03/2026

Enjoyed doing this interview for the @PLOS Climate Latitude blog! I discuss some of my recent PhD research on climate overshoots and temporary carbon storage. Check out the full interview below:

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 13/01/2026

Happy to announce that I passed my PhD defence yesterday!! Thanks to my supervisor @damonmatthews.bsky.social and the members of my examining committee — @nadinemengis.bsky.social, @gidden.bsky.social, Kirsten Zickfeld, and Sam Rowan

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 09/10/2025

That's why carbon removal should be the last resort, not Plan A. Stopping the burning of fossil fuels must be the priority. Thanks to falling renewable costs, that’s getting easier every year

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 09/10/2025

I’m all for R&D and investment in carbon removal — it matters for hard-to-decarbonize sectors. But relying on it to offset avoidable fossil emissions doesn’t make sense when electrification and non-emitting electricity can eliminate most emissions far more affordably and at scale.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 09/10/2025

So, does it make sense to keep burning fossil fuels for power and then try to pull that CO₂ back out of the sky later?Not really. On average, renewables are already cheaper than fossil fuels – even if we don't include the cost of CO₂ removal.

ourworldindata.org

Why did renewables become so cheap so fast?

In most places, power from new renewables is now cheaper than new fossil fuels.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 09/10/2025

How many plants like one proposed in Manitoba would we need to offset even one quarter of global CO₂ emissions at today's rate of emission? ~20,000 plants. That’s $10 trillion to build at the current price — not counting operating costs.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 09/10/2025

A new $500-million Deep Sky DAC plant is planned for Manitoba. It’s designed to remove 500,000 tonnes of CO₂ per year — which equals just six and a half minutes of global emissions at today’s rate of emission

theglobeandmail.com

Deep Sky unveils plans for one of the world’s biggest direct air carbon capture facilities in Manitoba

The plant, when fully complete, will absorb 500,000 tonnes of carbon dioxide annually, the Montreal-based company says

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 09/10/2025

Direct air capture (DAC) is the only truly durable carbon removal tech we have right now. The biggest DAC plant on Earth? It’ll capture just 900 tonnes of CO₂ (at $1000/tonne) in its first year of operation. That's less than 1 second worth of the 40 billion tonnes of CO₂ we emit each year.

oilprice.com

The Collapse of Confidence in Carbon Capture | OilPrice.com

Carbon Capture and Storage, once seen as a lifeline for the oil and gas industry, is facing mounting doubts as delays, high costs, and poor performance cast serious doubts on its future viability.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 09/10/2025

Don’t let anyone fool you into thinking carbon dioxide removal is the solution to climate change. It’s a small piece of the puzzle. But it won't be able to offset a substantial portion of our fossil fuel emissions 🧵

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 30/04/2025

Read the abstract here if you’re into the details: 🔗 doi.org/10.5194/egus... More coming soon on this work!

doi.org

Abstract EGU25-7422

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 30/04/2025

For global temperature ✅ If we're rapidly cutting emissions, temporary CDR can help reduce peak warming. ⚠️ If emissions stay high past 2100, it only delays the heat—not avoids it.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 30/04/2025

Think reforestation that sequesters CO₂ now, but gets cut or burned later. Even though the carbon is re-emitted, we found there's still a benefit to temporary carbon storage —especially for slow climate responding variables like sea level rise.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 30/04/2025

We looked at the climate impact of temporary carbon dioxide removal (CDR)—when carbon is captured but not stored forever.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 30/04/2025

Just presented some of my ongoing research at #EGU25 in Vienna! A thread...

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 22/04/2025

This difference in time horizons highlights why monitoring, reporting, and verification of land emissions and removals is essential, and why carbon markets must find robust methods to account for carbon losses due to disturbance.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 22/04/2025

The timescale in which CO2 impacts temperature is 1000s of years. The longevity of nature based CDR is dynamically linked to climate and operates on much shorter timescales.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 22/04/2025

The land sink is uncertain in a changing climate. This is another reason why using nature-based carbon dioxide removal (CDR) to offset fossil emissions can be sketchy...

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 23/01/2025

We should point to the rising costs of insurance to demonstrate that climate change is dangerous and is worth mitigating against/ adapting to. I suspect that, for many folks, $$ is easier to understand than climate observations and projections. Informative podcast on insurance and climate change

podcasts.apple.com

How Wildfires Destroyed California’s Insurance Market

Podcast Episode · Shift Key with Robinson Meyer and Jesse Jenkins · 2025-01-22 · 1h 12m

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 09/01/2025

Hi Paul! I'm a student researcher with the ECCC CCCS for a bit over a year now. Could you add me to your list?

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 06/12/2024

Great reads. I've always believed that changes in the insurance industry are a powerful tool for driving momentum for climate policy. Unlike many other industries, private insurance can't afford to ignore climate impacts or delay action (state-run insurance is a bit different)

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 04/12/2024

But I am aware that we need to reduce our meat consumption and think it's an important part of climate mitigation. I just think there are important distinctions

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 04/12/2024

If you emit 100 Gt CO2e through raising cattle and then stop, the CO2 portion from LUC would be mostly reversed as the forest/grasslands regrow. The methane contribution to warming will also mostly be gone after 25 years.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 04/12/2024

Well if we're trying to limit warming in the long term it matters. Let's say 100 Gt CO2 are emitted from coal and from raising cattle. For the 100 Gt CO2 from burning coal, the only way to truly reverse the warming effects in the long-term is using DACCS.

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Mitchell Dickau, PhD @mitchelldickau.bsky.social · 04/12/2024

It's 80x more powerful, but with a steady rate of emissions, the contribution to warming from CH4 is also mostly steady (perhaps a slight increase) because methane has a much shorter atmospheric lifetime.

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