Abrupt Change – Past, Present and Future

The Hard Reality, and the Silver Lining, in a Sustainable Future

Jim White, Director, INSTAARUniversity of Colorado Boulder

2014 Stefansson Memorial Lecture

Vilhjálmur Stefansson

Context

• We are in the midst of climate change, but HOW climate changes will be critical to adaptation.

• In adapting to change, “speed kills.”

• So understanding, and preparing for abrupt change is critical.

Defining abrupt climate change

• No universally accepted definition.

• In general, one needs:

– A fast change (much less than a human lifetime)

– A big change (in average or in variability)

– A change that seems out of proportion (too big) relative to the suspected cause

Moon Lake, ND, (Laird et al, 1996)

Abrupt Impacts of Climate Change:

Anticipating Surprises

New study from the US National Academy of Sciences:

Follow on from 2002 NRC report

This report also considers abrupt climate impacts:

Steady changes in climate and/or environment that trigger abrupt shifts in related human and natural systems

Abrupt Climate Impacts

Abrupt Change: abrupt climate change and abrupt impacts

• Scale in time and magnitude are relative to, and faster and larger than expectations and ability to adapt, including economic ability

– Air conditioning example

– New York City subway example?

Change won’t always be obvious: Timing and tipping points

• Abrupt changes, tipping points… a point of no return is crossed resulting in large, inevitable change.

• The“canoe on the Niagara River” type events: strong positive feedbacks

On the edge already

• The earth is more vulnerable to abrupt change today

– We have altered the earth’s energy balance and changed climate

– We cause 10 times more erosion than all natural processes

– We make more nitrogen fertilizer than all bacteria on land

– We make more sulfate than all ocean phytoplankton

How did this sneak up on us?Reason #1: Population

You are here

Reason #2: Use per capita, the multiplier

Low income is 3.5

times below middle

income, and 7 times

less than high income

The Nasty Dilemma:

we want others to live

well, but if they do, the

energy and resource

needs will be

staggering

Abrupt change: the past

• Abrupt change is a common and natural feature of the Earth’s climate system

• Up until the 1990’s we thought of climate change as mostly “gradual”, forced primarily by sun-earth changes

• Greenland ice cores and ocean sediment cores changed that view…

NEEMIce core sites

Abrupt events: the ice core view

Green is Greenland temperatureBlue is sea level

Dansgaard-Oeschger events

Last ice age

Abrupt change: the early storyYounger Dryas Termination

Willi Dansgaard

SigfusJohnsen

Dansgaard, White and Johnsen, Nature, 1989

Abrupt climate

changes: the story evolves

•>10˚C increase in Greenland temperature in 50 years•Double snow in 1 to 3 years•Sea ice retreat in 1 to 2 years•CH4 up 50% in 50 years•N2O up 10% in 50 years

Copenhagen to Gibraltar is 10˚CAtlanta to Minneapolis is 9˚C

d-excess comparison among three cores across 350 years:

NGRIP and GISP2 and NEEM

NEEM - NGRIP synchronizing match points (S.O. Rasmussen)

0

2

4

6

8

10

12

14

16

14500 14550 14600 14650 14700 14750 14800 14850

Bølling WarmingD

eute

riu

m e

xce

ss

GICC05 age (b2k)

Shift in 1 to 2 years

Multiple cores: signal versus noise

Recent breakthroughs in analytical systems allow us to look at sub-annual variations in multiple cores rapidly and more accurately

How abrupt is abrupt?

-380

-360

-340

-320

-300

-280

-260

-240

11500 11600 11700 11800 11900 12000

Younger Dryas Termination

D

GICC05 age (b2k)

NGRIPGISP2

~1˚C per year for 5 years in each step… 100 times faster than current warming

Stunningly abrupt: Bølling warming in northern Greenland

NGRIP and NEEM

NEEM - NGRIP synchronizing match points (S.O. Rasmussen)

-380

-360

-340

-320

-300

-280

-260

-240

14500 14600 14700 14800 14900 15000

Bølling warming

D

GICC05 age (b2k)

Isotope change in 1 to 2 years in 2 cores…Rate of inferred warming at northern sites 5-10 C per year!!!

Up to 1,000 times faster than current warming

Not all abrupt changes are equally abrupt everywhere

A climate threshold in northern Greenland?

Abrupt change: the present

• We are experiencing abrupt change today

– Arctic sea ice

– Groundwater loss

– Species extinction

– Ocean acidification

Abrupt Climate Changes and Impacts Now Underway

• Disappearance of summer time Arctic sea ice

– Faster than anticipated

• Impacts on Arctic ecosystems, changes to shipping, coastal erosion

Abrupt change is happening NOW

Arctic Sea IceWWW.climate.gov (NOAA)

Ice melt in water is highly non-linear

Lake Erie ice melts…in 2 weeks… that’s ~27,000 sqkm (Massachusetts, or 6.8 Rhode Islands)

Lake Erie example from 1973

The new frontier!

Abrupt changes now: Groundwater loss

Trends in groundwater storage: 2002-2010 GRACE

Abrupt change: the future

• Many thresholds of interest…– Sea level rise rate

– Species loss, marine and terrestrial

– Droughts and floods (water extremes)

– Oceanic oxygen minima zones

• Others concerning, but not abrupt– Permafrost carbon

Pika

corals

It is normal on earth to trade sea water for land ice… very simple

physics

Foster and Rohling, PNAS

The surprising reality of sea level change

Credit: PBS: ExtremeIce

The dynamic range of sea level change is difficult for people to grasp.

Over 500 feet of ocean is traded for land ice and vice versa

Major glaciations (20,000 years ago) = 400 feet lowering

Melt Greenland and Antarctica = 170 feet higher

Sea level rise (SLR) rate

• The rate of SLR is currently such that we expect about 1m of SLR by 2100.– Rates of 3 to 5 times faster are

common in the past record.

– Abrupt change: 1m in 100 years is fundamentally different than 1m in 30 years, or 20 years.

• The 3 “hows”: – How fast?

– How far?

– How inevitable?

Sea level is rising: 1 meter by the end of this century is current estimate… and it won’t stop there…

The reality of sea level rise

Miami Beach Mayor Philip Levine said the city is too valuable to lose, with real estate worth more than $23 billion and tourism revenue over $9 billion. Washington Post, 23/4/14

Marine based ice

• West Antarctica is a Marine Ice Sheet… its bedrock is well below sea level

Importance of Grounding Line

The long, slow, losing battle

Abrupt points:• Federal flood insurance• Property values• Key infrastructure• Fresh water

How inevitable?

Political tipping points?Are the troops on the frontlines getting restless?

“Deep time” sea level and temperature: Ultimate SLR

David Archer

Last time Earth had 400 ppm CO2

How far?

“Deep time” sea level and temperature: Ultimate SLR

Foster and Rohling, PNAS

~14 m is the sea water stored in West Antarctica and Greenland

How far?

What does 13 meters of sea level rise look like?

All maps: Flood.firetree.net

What does 13 meters of sea level rise look like?

What does 20 meters (65 feet) of sea level rise look like?

What does 20 meters (65 feet) of sea level rise look like?

Is it all about how you frame the conversation?

From Dawgsports.com

Need For Action

• It is time to take concrete steps; an early warning system is needed

– Useful vehicle towards action

– Builds on existing systems

– Helps arguments for continued monitoring

– No need to argue attribution

Final (positive!) thoughts…

A water world

Ours is a water planet and it takes time to heat up the water:

– The impacts (warmer) come after the causes (increased GHGs) by 50 years or more

– Leads to intergenerational inequity

The good news

Ethics and sustainability

My 3 simple rules of sustainability:

1. Everything must cycle2. Population must be

controlled (equality of the sexes), and vary inversely with resource use per capita

3. Equity must be considered and acted upon

Abrupt Impacts of Climate Change:

Anticipating Surprises

National Academy Press

www.nap.edu

Committee Members

• James White (Chair)– University of Colorado at Boulder

• Richard Alley– Pennsylvania State University

• David Archer– The University of Chicago

• Anthony Barnosky– University of California, Berkeley

• Jonathan Foley– University of Minnesota

• Rong Fu– The University of Texas at Austin

• Marika Holland– National Center for Atmospheric

Research

• Susan Lozier– Duke University

• Johanna Schmitt– University of California, Davis

• Laurence Smith– University of California, Los

Angeles

• George Sugihara– University of California, San Diego

• David Thompson– Colorado State University

• Andrew Weaver– University of Victoria, British

Columbia

• Steven Wofsy– Harvard University