The Earth is currently undergoing a significant transformation due to global warming. The cumulative impact of these changes is leading us to what are known as ‘tipping points’ in the climate system.
Key indicators of these changes include the shrinking of ice sheets, rising sea levels, and the widespread die-off of coral reefs. These events are not just isolated occurrences. They represent a continuous breaking of climate records and signal a shift in the fundamental workings of the Earth system.
“The Global Tipping Points Report,” the most comprehensive assessment of tipping points ever conducted, indicates that humanity is currently on a disastrous trajectory. Climate scientists reveal that the world is at a pivotal moment, with threats from Earth system tipping points and progress towards positive tipping points both accelerating.
The concept of ‘tipping points’ in climate science is crucial. According to the Intergovernmental Panel on Climate Change (IPCC), these tipping points are defined as “critical thresholds in a system that, when exceeded, can lead to a significant change in the state of the system, often with an understanding that the change is irreversible.”
In simpler terms, these are points in the Earth’s system where minor changes can initiate self-reinforcing loops. These loops push the system from one stable state into a drastically different and often irreversible state.
A clear illustration of such a tipping point is the potential transformation of rainforests into dry savannas due to a rise in global temperatures, primarily caused by fossil fuel burning. Such changes are driven by feedback loops that continue even if the initial cause ceases.
For instance, a forest ecosystem might remain in its ‘tipped’ state even if temperatures drop below the critical threshold.
These shifts can take decades or centuries to stabilize in a new state. However, if tipping points are being crossed currently or in the near future, the full scope of their impact might not be evident for centuries.
The crossing of one tipping point can trigger additional tipping elements. Consequently, this creates a domino effect that may render some areas less suitable for human and natural systems.
For example, the Arctic region is warming at a rate almost four times faster than the global average. This leads to accelerated ice melt and potentially impacting global ocean circulation and monsoon patterns. Such changes could increase drought frequencies in regions like the Amazon rainforest, further intensifying global warming.
In the early 2000s, scientists first identified a range of tipping elements, with the assumption that they would be activated with a global temperature rise of 4°C.
However, advancements in scientific understanding have led to a reevaluation of these elements. They now include the cryosphere, ocean-atmosphere systems, and biosphere, encompassing phenomena from the melting of polar ice sheets to coral reef die-offs.
The recently published “Global Tipping Points Report” highlights that five major systems are already at risk at the current level of global warming. These include the Greenland and West Antarctic ice sheets, permafrost regions, coral reefs, and specific ocean circulation patterns.
Since the Industrial Revolution, our planet has warmed by approximately 1.2°C. Sadly, current pledges under the Paris Agreement are setting us on a path towards a 2.5°C — 2.9°C rise in temperature this century. Recent evaluations have determined that surpassing a 1.5°C increase in global warming poses the risk of crossing several thresholds for climate tipping points.
Earth observation plays a vital role in monitoring and understanding these climate tipping points. Satellites provide comprehensive views of Earth’s systems. They enable scientists to track changes in polar ice, deforestation rates, ocean temperatures, and other critical indicators.
Satellites such as ESA’s CryoSat and Copernicus Sentinel-1 are instrumental in measuring changes in ice volume and flow. Others, providing data on gravity, help ascertain the extent of ice loss in polar regions. This information is crucial in identifying potential tipping points in ice sheet stability and their response to climate change.
Moreover, optical satellites like Sentinel-2 are pivotal in monitoring changes in land cover or vegetation, including the health of ecosystems like the Amazon rainforest. Missions like ESA’s Soil Moisture and Ocean Salinity (SMOS) satellite and the upcoming Fluorescence Explorer (FLEX) contribute to our understanding of soil moisture and vegetation health. This information then helps scientists assess terrestrial ecosystem resilience to climate impacts.
In terms of ocean circulation, satellites such as Sentinel-3 and SMOS offer insights into sea surface temperatures, currents, and salinity. They shed light on the dynamics of systems like the Atlantic Meridional Overturning Circulation.
The data captured by these satellites is invaluable for the early detection of environmental shifts. This information enhances our understanding of complex climate phenomena. It is critical in developing effective strategies for climate mitigation and adaptation.
The report presents six key recommendations:
In summary, the “Global Tipping Points Report” serves as a wake-up call and a guide for humanity at this pivotal moment. It outlines the imminent dangers of negative tipping points and the transformative potential of positive ones. The choices made now will determine the future trajectory of our planet and its inhabitants.
As the Earth system approaches these tipping points, the role of comprehensive observation and understanding becomes more crucial than ever in guiding our responses to these unprecedented changes.
Parts of the Global Tipping Points Report are published in a special issue of the journal Earth System Dynamics.
Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates.