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Cópia de Sea level rise update
2
SEA LEVEL RISE UPDATE
IT'S PROBABLY WORSE THAN YOU THINK!
Prezi presentation adapted from content by Ryan Hagen; original available at:
https://www.linkedin.com/pulse/sea-level-rise-update-its-probably-worse-than-youthink-ryan-hagen/
Key Takeaways
Last time Earth got this hot, sea levels were way higher.
Sea levels will likely be at least
3.3 ft (1 m)
Key Takeaways
higher by 2100.
In the long run,
7.5 ft (2.3 m)
of sea level rise is already locked-in.
Ice loss in Greenland and Antarctica
is decades ahead of schedule.
There's been a significant acceleration.
The fact of the matter is that coastal cities around the world will eventually have to make sci-fi adaptations or retreat.
Adaptations
Adaptations
The Scene
7 to 8 inches
Sea levels have gone up since 1900
Contributions come from:
Expansion of the ocean as it gets warmer;
Temperate land ice;
Greenland and Antarctica;
The Scene
Greenland & Antarctica
Greenland
& Antarctica
Recently, Greenland and Antarctica (the two ice behemoths) have started to chip in faster.
They are the X factors of rising sea levels.
Scientists have severely underestimated just how fragile they are.
Melting Giants
Now imagine that ice cube covering all of Mexico and the United States.
Imagine an ice cube that’s over 1-mile high.
Melting
Giants
That’s how big Antarctica is.
It holds enough ice to raise sea levels by 188 feet (57 meters).
Antarctica Loss
It takes every country on Earth a combined 10 days to use that much water.
Antarctica is now losing
252 billion tonnes
Antarctica Loss
of ice each year.
Antarctica actually loses over 2 trillion tonnes each year, but makes up for most of it with gains from snowfall.
Significance
That means Antarctica is losing ice at a rate of
Significance
3 Olympic swimming pools every second (net)
That’s 6 times faster than the rate 40 years ago. This is largely due to warmer ocean water.
Greenland
Greenland is as big as Germany, France, Spain, and Italy combined.
It holds 24 feet (7m) of sea-level rise at bay in its ice.
Like Antarctica, Greenland is losing ice 6 times faster than it was in the 1980s.
Greenland
286 billion tonnes
per year now.
That would be like
2,000 Elephants
charging into the ocean every second.
Significance
Significance
They thought Antarctica, in particular, was much more stable than it is.
Scientists
Scientists
Scientists have been caught off guard by the rapid acceleration of ice loss.
Projections
Projections
As they learn more about feedback loops and gain access to high-quality observational data from satellites,
they are significantly raising their sea-level rise projections from as recent as a few years ago.
Sensitivity
“At every point, as our knowledge increases, we’ve always discovered that the climate system is more sensitive than we thought it could be, not less.”
Dr. Maureen E. Raymo
Sensitivity
Acceleration
We have not seen the last of glaciers as big as Manhattan calving into the water.
These ice giants haven’t raised sea levels by much so far, but the key thing to know is that the rate of ice loss is accelerating, think exponentially, not linearly, compounding over time.
Acceleration
Non-Linear
As James Hansen says:
“The disintegration of ice sheets is likely to be highly non-linear.”
Non-Linear
Hotter Oceans
Ice is melting at faster and faster rates. There's enough ice at the poles for
212 feet of sea-level rise
This increase is in addition to melting glaciers and oceans that are expanding, simply because it’s getting hotter
Hotter
Oceans
Oceans absorb 90% of the additional heat from global warming
90%
Questions
It’s not a question of,
“Will sea levels rise?”
Questions
But, “How much and when?”
And, in the long run, how much sea-level rise is already locked-in?
Sea Levels
Sea Levels
What Were Sea Levels Like Last Time Earth Got This Hot?
Really high. We’ve already left the atmospheric conditions under which civilization developed.
As far as we know, we did it way faster than the climate has ever changed in the past naturally.
Reaction
Reaction
Luckily, it takes a little bit of time for the planet’s temperature and ice to fully react to our greenhouse gas emissions.
If you look at sea levels the last time Earth was this hot or had this much CO2 in the atmosphere it becomes abundantly clear that we need to eliminate emissions immediately.
Eliminate Emissions
Eliminate Emissions
Numbers
CO2 is increasing by 3 ppm each year.
Numbers
1ºC
We’ve raised the temperature by
3 / 4ºC
And are on track for
Sea levels are up 6 to 8 inches since the 19th century.
The Earth has been in this position before — but last time, the sea level was way higher.
History
History
We’ve just changed everything so quickly that it hasn’t had time to catch up yet.
History Repeats Itself
“We know that in the Earth’s history when ice sheets have collapsed and sea level has gone up, we’ve had the sea level rise of several meters in a century.
History Repeats Itself
So now, with humans changing the composition of the atmosphere much faster than it ever was changed in the past, there’s no reason to think that that couldn’t happen again.”
James Hansen
Projections
Nobody is talking about projections past the year 2100.
Projections
If we wave a magic wand and eliminate greenhouse gas emissions today, the momentum of the damage we’ve already done (1°C warming) would eventually raise oceans by
7 feet (2,3 m)
Perspective
Boston, as we know it, would cease to exist. Along with pretty much every other coastal city.
Perspective
Scientists estimate there will be about
Seven feet of sea-level rise, is like the ocean swallowing up the amount of land equal to Alaska, or four times the size of California, or six times the size of Italy, or seven and a half times the size of the United Kingdom.
2.3 meters (7.5 feet)
every 1°C
of warming.
Warming
Locked-in sea level rise
2010 global population below locked-in sea level
1.5°C
2.9 Meters
137 Million
Numbers
2°C
4.7 Meters
280 Million
3°C
6.4 Meters
432 Million
Numbers
4°C
8.9 Meters
627 Million
Social Impact
Social Impact
This is more of a social problem than a scientific one.
We’re talking about people’s lives here.
To 3°C / 4ºC
Where we're currently headed
Plug in your city on these numbers.
See how it transforms from 1°C
of warming (where we are now).
To 1°C
Paris Target
Expectations
Expectations
Understand that coastal shorelines are going to be on the move for the rest of your life.
But exactly how far they come depends on a few things.
Factors
How much more greenhouse gas emissions get dumped into the atmosphere.
Factors
Whether any natural tipping points that lead to runaway warming are triggered.
Just how sensitive Greenland and Antarctica’s ice sheets turn out to be.
How much heat the disrupted climatic system directs towards Greenland and Antarctica (above and below the ocean’s surface).
Scientists’ Predictions
As of today, scientists expect between 1 and 8.4 feet of sea-level rise by 2100
0.5 to 2 feet by 2050
0.3 to 2.5 m and 0.15 to 0.65 m respectively
Those are global averages.
Scientists’ Predictions
East Coast
The East Coast of the US, for example, will have a higher sea-level rise (~33%) than the global average due to changes in Earth’s gravitational field, rotation, and ocean circulation.
East Coast
Boston
Boston will likely have
Boston
1.4 to 11.1 feet by 2100
0.5 to 3.75 feet by 2050
according to NOAA’s latest projections.
Perspective
If we are able to really get our act together and stabilize temperatures under 2°C (~5% chance), most studies say sea level will be kept between
0.66 and 3.6 ft
by 2100 (0.2 to 1.1 m)
Stabilization
Significance
Significance
Between the consistent, overly-conservative projections over time, an evolving understanding of how ice sheets collapse, the exclusion of important feedback loops for further warming in models, and historical sea levels rising as quickly as four meters per century, assume there will be more than 1 meter of global sea-level rise by 2100.
The recent acceleration that has caught everyone off guard will continue.
The susceptible West Antarctic Ice Sheet, in particular, containing multiple meters of sea-level rise on its own, will reach a point of no return in all but the most aggressive emission elimination scenarios.
Acceleration
Acceleration
Disruption Speed
NOAA examined
Disruption Speed
90 cities on the US Coastline
and found that most, with only 0.35 m (<14 inches) of local sea-level rise...
...would face disruptive/damaging flooding 25 times more often by ~2040 under the “Intermediate” scenario.
And they will reach further and further inland. Nuisance or high-tide flooding will also continue to happen more frequently.
Floods
Floods
There will be more floods.
Those floods will be more damaging.
Consequences
Property values will continue to decline, flood insurance will become too expensive for many, freshwater supplies will be contaminated,
Consequences
subways will be increasingly inundated, risk of water-borne diseases will go up, and a whole host of other issues will arise.
Crisis
Crisis
No matter how much sea-levels rise, millions of people will be forced to leave their homes.
Where will they go?
This is a recipe for a global humanitarian crisis.
What to do
What to do
We need to wake up, and help other people wake up. We need to tell people, in plain terms, what the latest science is saying.
We need to tell people what is in store for us if we don’t start getting out of our comfort zones and taking action with others to systematically eliminate emissions.
Action
There are many things you can do. But this is a clever and fun one.
Jon Leland had an idea:
Put biodegradable stickers in places that will eventually be underwater with just 2°C of global warming.
People put them in influential places.
Action
Impact
Impact
Seeing the stickers, people will better understand how climate change could impact their community.
Pictures can also be spread and tagged on social media with:
#ThisPlaceWillBeWater
Motivation
Others say fear is a better motivator.
We need some of both. They each have a time and place.
Some people say that we must be optimistic and hopeful in order to encourage others to take action.
Motivation
Think About It
As Jon puts it,
Think
About It
“People don’t want to think about climate change because it’s scary. Well, they need to think about it. And they need to be scared.”
Spread the Word
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and get some stickers!
Use the #ThisPlaceWillBeWater https://www.thisplacewillbewater.org/