Global tipping points
Tipping points shown in Fig. 1 have global physical, economic, and social impacts outside the scope of this website. For further information see Carbon Brief’s website , Video 4 below, and this this free to access paper in the journal Nature.
“The observed temperatures were so extreme that they lie far outside the range of historically observed temperatures. – Lead researchers interviewed in Carbon Brief
We may be able to reverse some tipping points if we can reverse rising temperatures by drawing down excessive carbon from the atmosphere. The fastest and most cost-effective way to achieve this is by restoring natural ecosystems, which will bring the collateral benefits of healthy ecosystem services as well as a livable climate.
Tipping points covered in more depth on this website:
Biodiversity loss:
Threats are from introduced pest plants and animals that thrive in a changing climate, ongoing agricultural expansion, pollutants entering waterways, demands for reliable water for irrigation, bulldozing marine ecosystems through bottom trawling, and an Emissions Trading Scheme that financially incentivises monoculture radiata pine plantations over the protection and restoration of biodiverse native ecosystems. Once tipping points for some native ecosystems and species are reached, the ecosystem services they provided (including flood mitigation, coastal defenses against rising sea levels, and long term carbon sequestration), are, along with some critically endangered species, gone forever.
“Since the 2012…over a hundred thousand hectares of true land-use change [has been] going on around wetlands, scrub being cleared, and dairy land-use intensification.” – Landcare Research, 2020
“Even the most egregious offences—including a dam built on a wetland, clearance of a nationally endangered form of kānuka, and aerial poisoning of swathes of regenerating native bush—often prompted little more than a warning from authorities.” – Charlie Mitchell, Stuff, 2020
The melting cryosphere:
“If current rates of surface lowering persist, the entire Thwaites Eastern Ice Shelf will unpin from the seafloor in less than a decade, despite our finding from airborne radar data that the seafloor underneath the pinning point is about 200 m shallower than previously reported. – Wild et al, 2021.
“Having two caps of a permanent ice in the Arctic and Antarctica is the very precondition for the planet to stay in a state that has enabled us to develop civilizations as we know it. Whether it’s a small glacier or whether we’re talking about Greenland, they all add together to this fantastic capacity of cooling the planet.
Icecaps and glaciers are reflecting back 90 to 95% of incoming heat from the sun. When these ice sheets start melting, you can come to a point where the ice sheets tip over from being self-cooling to becoming self- warming and that is the most dramatic tipping point in their system. A tipping point is the point beyond which a change becomes irreversible. So in the current climate, Greenland is already beyond its threshold where it’s now losing 10,000 cubic metres of ice per second. That loss rate will only continue as the climate heats up.
So is Greenland lost? Evidently, it is.
The drama here is that one characteristic of tipping points is that once you press the on button you cannot stop it. It takes over. It’s too late. It’s not like you could say, ‘Oops now I realise I didn’t want to melt the Greenland ice sheet. Let’s back off.’ Then it’s too late.
The important point to make here is that everything in the Earth system is connected. When one part of the climate system crosses its tipping point, then that might make it more likely for other parts of the system to also cross their critical thresholds. So you can think of this in terms of dominoes. If you tip one of them over, then this might lead to cascading effect. When we cross tipping points, we unleash irreversible changes that would mean that the planet who go from are best friend, where it dampens and reduces the stress, sucking out carbon dioxide and taking up heat-absorbing impacts, and tipping over to a point where it could self-reinforce warming. – Breaking Boundaries: The Science of our Planet (Video 1).
“In New Zealand, 72,000 people are currently exposed to present-day extreme coastal flooding, along with about 50,000 buildings worth $12.5 billion. The risk exposure increases markedly with sea-level rise, particularly during the first metre of rise…. There is near certainty that the sea will rise 20-30cm by 2040.” – NIWA
Video 2: Steffen M. Olsen, Danish Meteorological Institute. The ice sheet near Qaanaaq Greenland that they would normally sled across is covered in vast meltwater lakes due to extreme surface warming (17°C) in June 2019. Meltwater eventually drains into the ocean, contributing to rising sea levels and disrupting oceanic currents.
Video 3: At COP26, over 100 countries including New Zealand signed a global pledge to cut methane emissions 30% below 2020 levels by 2030 in recognition of the serious threat we face today. “Many scientists are convinced there is a real threat of a methane bomb or methane outbreak of very large magnitude sufficient to perhaps cause an immediate warming of at least one degree.”
Video 4: This video starts 17 minutes into the 42-minute presentation from Earth Systems scientist Professor Will Steffen (Climate Council of Australia, Australian National University). The full video is an ideal starting point for students of all ages to understand how Earth has operated over the past 4.6 billion years, and the impacts of climate change.