NZ Herald
  • Home
  • Latest news
  • Herald NOW
  • Video
  • New Zealand
  • Sport
  • World
  • Business
  • Entertainment
  • Podcasts
  • Quizzes
  • Opinion
  • Lifestyle
  • Travel
  • Viva
  • Weather

Subscriptions

  • Herald Premium
  • Viva Premium
  • The Listener
  • BusinessDesk

Sections

  • Latest news
  • New Zealand
    • All New Zealand
    • Crime
    • Politics
    • Education
    • Open Justice
    • Scam Update
  • Herald NOW
  • On The Up
  • World
    • All World
    • Australia
    • Asia
    • UK
    • United States
    • Middle East
    • Europe
    • Pacific
  • Business
    • All Business
    • MarketsSharesCurrencyCommoditiesStock TakesCrypto
    • Markets with Madison
    • Media Insider
    • Business analysis
    • Personal financeKiwiSaverInterest ratesTaxInvestment
    • EconomyInflationGDPOfficial cash rateEmployment
    • Small business
    • Business reportsMood of the BoardroomProject AucklandSustainable business and financeCapital markets reportAgribusiness reportInfrastructure reportDynamic business
    • Deloitte Top 200 Awards
    • CompaniesAged CareAgribusinessAirlinesBanking and financeConstructionEnergyFreight and logisticsHealthcareManufacturingMedia and MarketingRetailTelecommunicationsTourism
  • Opinion
    • All Opinion
    • Analysis
    • Editorials
    • Business analysis
    • Premium opinion
    • Letters to the editor
  • Politics
  • Sport
    • All Sport
    • OlympicsParalympics
    • RugbySuper RugbyNPCAll BlacksBlack FernsRugby sevensSchool rugby
    • CricketBlack CapsWhite Ferns
    • Racing
    • NetballSilver Ferns
    • LeagueWarriorsNRL
    • FootballWellington PhoenixAuckland FCAll WhitesFootball FernsEnglish Premier League
    • GolfNZ Open
    • MotorsportFormula 1
    • Boxing
    • UFC
    • BasketballNBABreakersTall BlacksTall Ferns
    • Tennis
    • Cycling
    • Athletics
    • SailingAmerica's CupSailGP
    • Rowing
  • Lifestyle
    • All Lifestyle
    • Viva - Food, fashion & beauty
    • Society Insider
    • Royals
    • Sex & relationships
    • Food & drinkRecipesRecipe collectionsRestaurant reviewsRestaurant bookings
    • Health & wellbeing
    • Fashion & beauty
    • Pets & animals
    • The Selection - Shop the trendsShop fashionShop beautyShop entertainmentShop giftsShop home & living
    • Milford's Investing Place
  • Entertainment
    • All Entertainment
    • TV
    • MoviesMovie reviews
    • MusicMusic reviews
    • BooksBook reviews
    • Culture
    • ReviewsBook reviewsMovie reviewsMusic reviewsRestaurant reviews
  • Travel
    • All Travel
    • News
    • New ZealandNorthlandAucklandWellingtonCanterburyOtago / QueenstownNelson-TasmanBest NZ beaches
    • International travelAustraliaPacific IslandsEuropeUKUSAAfricaAsia
    • Rail holidays
    • Cruise holidays
    • Ski holidays
    • Luxury travel
    • Adventure travel
  • Kāhu Māori news
  • Environment
    • All Environment
    • Our Green Future
  • Talanoa Pacific news
  • Property
    • All Property
    • Property Insider
    • Interest rates tracker
    • Residential property listings
    • Commercial property listings
  • Health
  • Technology
    • All Technology
    • AI
    • Social media
  • Rural
    • All Rural
    • Dairy farming
    • Sheep & beef farming
    • Horticulture
    • Animal health
    • Rural business
    • Rural life
    • Rural technology
    • Opinion
    • Audio & podcasts
  • Weather forecasts
    • All Weather forecasts
    • Kaitaia
    • Whangārei
    • Dargaville
    • Auckland
    • Thames
    • Tauranga
    • Hamilton
    • Whakatāne
    • Rotorua
    • Tokoroa
    • Te Kuiti
    • Taumaranui
    • Taupō
    • Gisborne
    • New Plymouth
    • Napier
    • Hastings
    • Dannevirke
    • Whanganui
    • Palmerston North
    • Levin
    • Paraparaumu
    • Masterton
    • Wellington
    • Motueka
    • Nelson
    • Blenheim
    • Westport
    • Reefton
    • Kaikōura
    • Greymouth
    • Hokitika
    • Christchurch
    • Ashburton
    • Timaru
    • Wānaka
    • Oamaru
    • Queenstown
    • Dunedin
    • Gore
    • Invercargill
  • Meet the journalists
  • Promotions & competitions
  • OneRoof property listings
  • Driven car news

Puzzles & Quizzes

  • Puzzles
    • All Puzzles
    • Sudoku
    • Code Cracker
    • Crosswords
    • Cryptic crossword
    • Wordsearch
  • Quizzes
    • All Quizzes
    • Morning quiz
    • Afternoon quiz
    • Sports quiz

Regions

  • Northland
    • All Northland
    • Far North
    • Kaitaia
    • Kerikeri
    • Kaikohe
    • Bay of Islands
    • Whangarei
    • Dargaville
    • Kaipara
    • Mangawhai
  • Auckland
  • Waikato
    • All Waikato
    • Hamilton
    • Coromandel & Hauraki
    • Matamata & Piako
    • Cambridge
    • Te Awamutu
    • Tokoroa & South Waikato
    • Taupō & Tūrangi
  • Bay of Plenty
    • All Bay of Plenty
    • Katikati
    • Tauranga
    • Mount Maunganui
    • Pāpāmoa
    • Te Puke
    • Whakatāne
  • Rotorua
  • Hawke's Bay
    • All Hawke's Bay
    • Napier
    • Hastings
    • Havelock North
    • Central Hawke's Bay
    • Wairoa
  • Taranaki
    • All Taranaki
    • Stratford
    • New Plymouth
    • Hāwera
  • Manawatū - Whanganui
    • All Manawatū - Whanganui
    • Whanganui
    • Palmerston North
    • Manawatū
    • Tararua
    • Horowhenua
  • Wellington
    • All Wellington
    • Kapiti
    • Wairarapa
    • Upper Hutt
    • Lower Hutt
  • Nelson & Tasman
    • All Nelson & Tasman
    • Motueka
    • Nelson
    • Tasman
  • Marlborough
  • West Coast
  • Canterbury
    • All Canterbury
    • Kaikōura
    • Christchurch
    • Ashburton
    • Timaru
  • Otago
    • All Otago
    • Oamaru
    • Dunedin
    • Balclutha
    • Alexandra
    • Queenstown
    • Wanaka
  • Southland
    • All Southland
    • Invercargill
    • Gore
    • Stewart Island
  • Gisborne

Media

  • Video
    • All Video
    • NZ news video
    • Herald NOW
    • Business news video
    • Politics news video
    • Sport video
    • World news video
    • Lifestyle video
    • Entertainment video
    • Travel video
    • Markets with Madison
    • Kea Kids news
  • Podcasts
    • All Podcasts
    • The Front Page
    • On the Tiles
    • Ask me Anything
    • The Little Things
  • Cartoons
  • Photo galleries
  • Today's Paper - E-editions
  • Photo sales
  • Classifieds

NZME Network

  • Advertise with NZME
  • OneRoof
  • Driven Car Guide
  • BusinessDesk
  • Newstalk ZB
  • Sunlive
  • ZM
  • The Hits
  • Coast
  • Radio Hauraki
  • The Alternative Commentary Collective
  • Gold
  • Flava
  • iHeart Radio
  • Hokonui
  • Radio Wanaka
  • iHeartCountry New Zealand
  • Restaurant Hub
  • NZME Events

SubscribeSign In
Advertisement
Advertise with NZME.
Home / World

What climate tipping points should we be looking out for?

By Andrew Glikson
Other·
15 Jul, 2014 05:17 AM6 mins to read

Subscribe to listen

Access to Herald Premium articles require a Premium subscription. Subscribe now to listen.
Already a subscriber?  Sign in here

Listening to articles is free for open-access content—explore other articles or learn more about text-to-speech.
‌
Save

    Share this article

Drifting ice sheets. Photo / Thinkstock

Drifting ice sheets. Photo / Thinkstock

The concept of a "tipping point" - a threshold beyond which a system shifts to a new state - is becoming a familiar one in discussions of the climate.

Examples of tipping points are everywhere: a glass falling off a table upon tilting; a bacterial population hitting a level where it pushes your body into fever; the boiling point of water, or a cube of ice being thrown into warm water, where it rapidly melts.

The ice cube is a poignant example, because scientists now fear that West Antarctica's ice sheets are also heading towards irreversible melting.

Likewise, the recent discovery of deep canyons beneath the Greenland ice sheet raises concerns regarding its stability.

The history of the atmosphere, oceans and ice caps indicates that, once changes in the energy level which drive either warming or cooling reach a critical threshold, irreversible tipping points ensue.

Advertisement
Advertise with NZME.
Advertisement
Advertise with NZME.

An example is a process called "albedo flip", where a small amount of melting creates a film of water on top of the ice. The water absorbs infrared radiation and melts more ice, leading to runaway melting of ice sheet. The opposite process occurs where the freezing of water results in reflection of radiation to space, leading to cooling and freezing of more water.

Other examples are abrupt warming episodes during glacial states, termed "interstadials", for example the "Dansgaard-Oeschger" warming cycles which occurred during the last glacial period between about 100,000 and 20,000 thousand years ago, which caused large parts of the North Atlantic Ocean to undergo temperature changes of several degrees Celsius within short periods. Other examples are points at which a glacial state ends abruptly to be replaced by rapid glacial termination.

Over the threshold

An increase in global temperatures can lead to a threshold representing the culmination and synergy of multiple processes, such as release of methane from permafrost or polar ocean sediments, retreating sea ice and ice sheets, warming oceans, collapse of ocean current systems such as the North Atlantic Thermohaline Current and - not least - large scale fires.

Advertisement
Advertise with NZME.

A major consequence of warming of ice sheets is the increase in supply of cold fresh melt water to adjacent oceans, such as the abrupt cooling of the North Atlantic Ocean inducing rapid freezing events (stadials), as represented by the "Younger dryas" event (12,900-11,700 years ago), or the rapid melting of Laurentian ice cap about 8500 years ago and related abrupt cooling events in Europe and North America.

Satellite images of Greenland, July 8 and July 12, 2012. White shows remaining ice; red shows melt; pink shows probable melt; grey shows ice-free; dark grey means no data. Image / NASA

The question is whether the post-18th century global warming trend may culminate in a major tipping point or, alternatively, is represented by an increase in disparate extreme weather events, as are currently occurring around the world.

A potential indicator of such tipping point may be represented by a collapse of the North Atlantic Thermal Circulation, which would lead to a sharp, albeit transient, temperature drop in the North Atlantic Ocean, North America and Western Europe. Evidence for a weakening of the North Atlantic deep water circulation by about 30 percent between 1957 and 2004 has been reported in Nature as well as by other researchers.

Discover more

Opinion

Lucy Lawless: It's a tricky world but good things are happening

12 Jun 04:15 PM
World

What's it like under the Indian Ocean?

17 Jun 04:36 AM
Business

Cloud can help NZ companies beat the tyranny of distance

09 Jul 05:00 PM
New Zealand

More rain to follow cold snap

15 Jul 08:19 AM

The question of tipping points is of critical importance since it affects future climate projections and adaptation plans. In this regard the latest Intergovernmental Panel on Climate Change report leaves the question of tipping points open.

The crucial question

So how likely is the current climate change trend to reach a tipping point, and if so of what magnitude and on what time scale?

General circulation climate models which attempt to delineate overall future climate trends are limited in their capacity to predict the precise timing, location and magnitude of abrupt climate and weather events with confidence.

Since the 19th century the rise in the energy level of the atmosphere has reached a level of more than 3 degrees Celsius when the masking effects of sulphur aerosols are discounted. This degree of temperature rise is just under the energy rise level associated with the last glacial termination between about 16,000 and 10,000 years ago.

The atmosphere-ocean system continued to warm following the peak El-Nino event of 1998. Most of the warming occurred in the oceans, whose mean temperature has risen by about 0.3C since 1950.

The current rise in atmospheric CO2 of about 2 parts per million CO2/year, reaching 401.85 parts per million at the Mauna Loa Observatory in Hawaii in May 2014, exceeds rates observed in the geological record of the last 65 million years.

Advertisement
Advertise with NZME.

An atmospheric CO2 level of 400 parts per million is estimated for the Miocene, about 16 million years ago, when mean temperatures have reached 3 to 4 degrees Celsius above those of pre-industrial temperatures. Economically available fossil fuel reserves, if used, are capable of returning the atmosphere to tropical state such as existed during the early to mid-Eocene prior to the formation of the Antarctic ice sheet about 32 million years ago.

The evidence indicates that, since the mid-1980s, the Earth is shifting from a climate state that favoured land cultivation since about 7000 years ago to a climate state characterised by mean global temperatures about 2-3 degrees Celsius above pre-industrial levels.

At this level, extreme weather events would render large parts of the continents unsuitable for agriculture. The accelerated melting of the Greenland and west Antarctic ice sheets could lead to conditions akin to those of the Pliocene, before 2.6 million years ago, when sea level were between 5 and 40 metres higher than at present, as estimated by the US Geological Survey.

The evidence indicates the climate may be tracking toward - or is already crossing - tipping points whose precise nature and timing remain undefined, depending on the extent to which ice sheet melting is retarded due to hysteresis. The increase in frequency and intensity of extreme weather events around the globe may represent a shift in state of the atmosphere-ocean system. There is no alternative to a global effort at deep cuts of carbon emissions coupled with fast-tracked CO2 sequestration.

As Professor Joachim Schellnhuber, Germany's climate advisor and Director of the Potsdam Climate Impacts Institute, has said:

Andrew Glikson does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.This article was originally published on The Conversation.
Read the original article.

Advertisement
Advertise with NZME.
Save

    Share this article

Latest from World

World

Mushroom poisoning trial: Court releases photos showing deadly beef wellington

07 Jul 08:51 AM
World

The moment Erin Patterson knew her fate was sealed

07 Jul 08:17 AM
Premium
Business|companies

Tech Insider: UK tells retailers to use NZ’s Auror crime-fighting software

07 Jul 07:00 AM

From early mornings to easy living

sponsored
Advertisement
Advertise with NZME.

Latest from World

Mushroom poisoning trial: Court releases photos showing deadly beef wellington

Mushroom poisoning trial: Court releases photos showing deadly beef wellington

07 Jul 08:51 AM

The leftovers were taken from Erin Patterson's bin.

The moment Erin Patterson knew her fate was sealed

The moment Erin Patterson knew her fate was sealed

07 Jul 08:17 AM
Premium
Tech Insider: UK tells retailers to use NZ’s Auror crime-fighting software

Tech Insider: UK tells retailers to use NZ’s Auror crime-fighting software

07 Jul 07:00 AM
Jury finds Erin Patterson guilty of murder

Jury finds Erin Patterson guilty of murder

Solar bat monitors uncover secrets of Auckland’s night sky
sponsored

Solar bat monitors uncover secrets of Auckland’s night sky

NZ Herald
  • About NZ Herald
  • Meet the journalists
  • Newsletters
  • Classifieds
  • Help & support
  • Contact us
  • House rules
  • Privacy Policy
  • Terms of use
  • Competition terms & conditions
  • Our use of AI
Subscriber Services
  • NZ Herald e-editions
  • Daily puzzles & quizzes
  • Manage your digital subscription
  • Manage your print subscription
  • Subscribe to the NZ Herald newspaper
  • Subscribe to Herald Premium
  • Gift a subscription
  • Subscriber FAQs
  • Subscription terms & conditions
  • Promotions and subscriber benefits
NZME Network
  • The New Zealand Herald
  • The Northland Age
  • The Northern Advocate
  • Waikato Herald
  • Bay of Plenty Times
  • Rotorua Daily Post
  • Hawke's Bay Today
  • Whanganui Chronicle
  • Viva
  • NZ Listener
  • Newstalk ZB
  • BusinessDesk
  • OneRoof
  • Driven Car Guide
  • iHeart Radio
  • Restaurant Hub
NZME
  • About NZME
  • NZME careers
  • Advertise with NZME
  • Digital self-service advertising
  • Book your classified ad
  • Photo sales
  • NZME Events
  • © Copyright 2025 NZME Publishing Limited
TOP