A meander thru a changing climate
Spurred by an upcoming John Muir Trail trip!
Inspired by my upcoming thru-hike on the John Muir Trail (JMT), we’re going to spend some time this week on an ever-present, but under-dissected topic on this blog… climate change!
Thanks for tuning in and remember to click “Subscribe now” if you like what you read and share with friends, family, and colleagues who might be interested as well!
P.S. For those wanting to learn more about my JMT trip, stay tuned for a mid-week edition including fast facts, climate-relevant data, beautiful scenery and even my packing list for the 2.5 week, 200+ mile trek!
A personal journey 🧘♂️
Humans make the world turn, and besides copious amounts of coffee, personal connection & inspiration makes us humans turn. Climate change is no exception.
When you talk to folks who have been involved in climate for the past 20+ years, you often hear career origin stories about seeing climate change first-hand — be it through shrinking alpine glaciers, shorter ski seasons, or even exotic trips near the Artic circle.
While I don’t have the notches on my belt to tell the same story, I can certainly remember years past where the snowmen, snow forts, and walks to the school bus were far colder, snowier, and more frequent than today.
Be that as it may, it can still be easy to brush over the physical changes that global warming is causing due to their chronic and distributed nature. And for those of us who aren’t climate scientists, it can be additionally challenging to paint a cohesive, clear, impactful mental narrative about climate change through one-off storms, warmer-than-average winters, and news stories about polar bears starving in the Artic.
So let’s take a shot at doing just that and hopefully inspire even more of this group to turn their personal and professional efforts toward this critical topic:
How do we know the climate is changing? (and that we are the cause)
Why is climate change trickier than you’d first expect?
What does this mean for you and me?
Climate science from a layman 🌎
A disclaimer to start: I am not a climate scientist by training.
However, I have had the pleasure of working closely with those who are and translating the impacts of physical climate change into the business world1.
So here’s my mental framing and understanding for how we know the climate is changing and human emissions (aka anthropogenic) are the cause:
Temperatures be rising… 🌡️
While temperatures have fluctuated widely over the history of the planet, we have seen remarkably stable temperatures for the last ~10,000 years. This stability is a primary reason for the advent and growth of thriving human civilizations.
However, since the turn of the 20th century, the global average temperature has increased by about 1.2 degrees Celsius — directly in coincidence with the industrial age and the advent of large amounts of man-made emissions. Not only have average temperatures increased, but extreme temperatures have increased. Think about a normal distribution curve: the center of the curve has shifted and the edges of the curve are flatter.
These observations have been supported and confirmed globally through countless satellites, monitoring stations, and discreet measurements.
Statistics be convincing… ➗
Rising global temperatures aren’t enough to attribute blame to mankind. As I mentioned, global temperatures have risen (interglacial) and fallen (glacial) throughout Earth’s history! However, the statistical correlation between rising GHG emissions and rising temperatures is… let’s say… convincing.
Scientists have scoured the list of possible reasons that global temperatures could be rising in the manner they have — including more incident sunlight on the Earth, natural changes in the atmosphere, and changing reflectivity — and they’re pretty convinced humans are the culprit.
How convinced? Scientists have assigned 5-standard deviations worth of confidence to this assessment.
To translate, that’s a 1 in 3.5 million chance that humans aren’t the cause. Now… that’s no 12-standard deviations of confidence first assigned to the observation of gravitational waves caused by black-holes colliding… but I’ll take it.
Changes be happening… 🧊
Throw the thermometers and statistics out the window and just look out the window! The changes caused by a warming globe are abundantly clear.
Artic ice sheets are going away — down 50% on average since 1980 and 70-90% of that loss is attributed to human activity.
The energy from a warmer climate is increasing severe events — making storms and wildfires 2-6x more likely to occur in certain geographies
You can feel the heat — 1 in 20 year temperature events now have a 75x higher likelihood of happening than they did 50 years ago.
Climate change is #deep 🧮
Now that everyone is aboard the climate change train — it’s time to dive a bit deeper. Climate change is a trickier beast than you imagined.
Climate inertia 🚆
Like any large body in motion, the climate has inertia as well! Once we stop emitting greenhouse gases, things don’t reverse immediately. In fact, climate scientists know that the next decade of warming is locked in. Yes, locked in.
That means no matter what we do — even if we stopped all emissions today — the globe’s warming through 2030 is happening whether we like it or not.
Geospatial variability 🔍
Climate does not treat everyone equally.
That 1.2 degrees Celsius of warming I mentioned? That’s not distributed evenly like a well-made PB&J. Over that same warming period, the Artic warmed about 4 degrees Celsius while parts of Africa have only warmed about 0.2-0.4 degrees Celsius.
This regional variability means that some parts of the globe are harder hit than others. Add to that regionality already fragile ecosystems that are struggling to manage frequent flooding, heat waves, and sea level rise… climate change is a bully that picks on those that are least suited to deal with it.
Ecosystem fragility & feedback 🌱
The Earth’s ecosystem and infrastructure built to interact with it are surprisingly fragile. This means that once the world starts changing, that change becomes non-linear, fast — growing and multiplying at higher rates than we might expect.
A perfect example of this is a biotic feedback loop — like thawing permafrost.
As the Artic continues to warm, the permafrost, or perpetually frozen tundra near the North Pole, begins to melt.
This permafrost happens to trap a lot of methane and carbon dioxide in its frozen confines — hundreds of billions of tonnes.
This means that the emissions contributing to global warming get a multiplier effect — think about it like one tonne of human emissions creates even more than one tonne of total emissions released.
These types of feedback could decrease our carbon budget by 10-20%. That’s scary.
So what? 🔥
So let’s translate all of this fancy science into some physical changes and risks that are expected to happen in an attempt to personalize the impact2:
1 billion people will have a ~15% chance of experiencing lethal heat waves annually by 2050. This combination of heat and humidity in places like India and Pakistan is not only deadly, but could drive mass population migration.
60% of the world’s food comes from 5 global ‘bread baskets’ — the likelihood of low yield harvests may increase by ~3x — further contributing to the food system stress that exists today (e.g., increasing population, hunger & poverty)
Billions of people living in the Mediterranean, United States, and beyond could see water basins decrease by as much as 70% in certain places. This can cause fresh water shortages that leave populations scrambling and impact the broader infrastructure base (e.g., industrial plant cooling, hydropower)
These changes are going to be here sooner than you think if we don’t get moving3.
Well… this was a rather bad news bears article. 🐻
I know I mention climate change in almost every post, but hopefully this article served to personalize and clarify the physical impact and changes that can take place.
Some good news to finish? 📰
The world is starting to wake up to these physical risks. One example:
The world’s financial system is rapidly working to assess the physical climate impacts that will affect their infrastructure and economic portfolio over the next thirty years.
When the sources of money start to ask questions, that pressure rolls down hill quick!
If you’re interested in personalizing this journey even more, check out some of the very cool geospatial analytics tools that are hitting the market — two of which being Cervest and Probable Futures. In a not so distant future, every major purchase you make will be informed by 30+ years of future climate scenarios.
Stay cool, stay well, and until next time…
Near the end of my McKinsey tenure in 2020, I spent a large share of my time translating the impacts of physical climate change into financial and operational risks for major institutions. This is where I learned what I know about the topic and sourced a large amount of these facts.
For anyone looking to go deeper, I recommend diving into the full McKinsey report, written in partnership with the Woodshole Research Center and many others.
+ Executive summary (~40 pages) click here
+ Full report (~150 pages) click here
All projections in this article came from the McKinsey Climate Risk report mentioned above. These changes are under an RCP 8.5 scenario — which is one of the higher emissions scenarios studied, but notably, is the emissions scenario that the world is tracking against.
Like I’ve said in past posts, it’s not too late to move to Michigan! All the fresh water you could want and wineries that are going to increase by a factor of 10 in the next 30 years! (let’s not talk about the quality of that wine OK…)