Anybody remember August 9th 2021?

A jump back to August 9th 2021, when the Intergovernmental Panel on Climate Change (IPCC) released its Sixth Assessment Report (AR6). ?This report focused on the physical science basis of climate change and provided updated information on the impacts and potential future risks of climate change.? The report categorically stated “It is unequivocal that human influence has warmed the atmosphere, ocean and land. Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred”.

The IPCC's sixth assessment warned that “we are running out of time to keep to 1.5°”, but “we have all the tools we need to get on track for net zero in time”.

The IPCC's recent reports have been dubbed a 'code red for humanity' and an 'atlas of human suffering'. (March 2023).

Warning, warning warnings, and what have we done about it?? Not much and certainly not fast enough. It is a stark reminder that our world is pushing the planet's thermostat beyond safe levels of 350 ppm CO2, and that more people (and governments commitments) are needed to combine our ingenuity and resources to keep the present overshoot in control. These rising levels are attributed to continued high fossil fuel emissions and recent El Ni?o conditions, which have reduced the capacity of global ecosystems to absorb CO2. The increasing CO2 levels are a critical indicator of ongoing climate change and emphasize the urgent need for reducing fossil fuel use and implementing sustainable practices to mitigate environmental impact.

When the trend for atmospheric CO2 begins to falter and fall, we can expect global average temperature to follow.? For those who care about the sustainability of the planet, and who want it to remain a place where people can flourish, the measured CO2 levels in the atmosphere serve as the single best, real-time signal of whether the world is on track to a safe future or needing to do more to get on track.?

The following chart will show us that since 2015 the ppm has risen from 401.10 ppm to the latest CO2 Earth update: 2:35:02 AM on Aug. 15, 2024, Hawaii local time (UTC -10) is 422.66 ppm.?

Despite all the stark warnings and scientific evidence, we (the collective ‘we’) continue to ignore the rise of CO2 and this puts us all in danger of overstepping the planetary boundaries.

The IPCC report details the increasing frequency and intensity of extreme weather events, such as heatwaves, heavy rainfall, droughts, and tropical cyclones, which have been exacerbated by human-induced climate change and we have certainly witnessed these extreme weather conditions during the last 3 years. To limit global warming to 1.5°C above pre-industrial levels, the report emphasizes the urgent need for immediate, rapid, and large-scale reductions in greenhouse gas emissions, noting that the remaining carbon budget to achieve this target is very limited. Sea levels are projected to continue rising for centuries, with an estimated increase of 0.3 to 1 meter by 2100, even with stringent mitigation efforts.

The current rise in sea temperatures is unprecedented in the modern era, but there have been periods in Earth's history when sea temperatures were similarly high or even higher. I like to look at comparative eras to see what is in store for us in the future if we continue on the path we are on now.? One such period was the Paleocene-Eocene Thermal Maximum (PETM), around 56 million years ago. It is interesting to look at some key points from this period and its consequences.

This period was likely triggered by massive releases of carbon into the atmosphere, possibly from volcanic activity, methane hydrate release, or other geological processes, it should be noted that we can now add human activity as one of the processes.

During the PETM, global temperatures rose by 5-8°C over a few thousand years. Sea surface temperatures in the tropics may have reached around 35°C, much higher than today's average of about 26-28°C.

This increased CO2 levels led to ocean acidification, impacting marine life, particularly organisms with calcium carbonate shells or skeletons, such as foraminifera and corals. Many marine species, especially deep-sea benthic foraminifera, experienced significant extinctions due to changes in temperature and chemistry. The warming altered ocean circulation patterns, potentially reducing the oxygen content of the deep ocean and creating more oxygen-depleted conditions. Warmer temperatures and acidification caused shifts in marine ecosystems, affecting the distribution and abundance of species.? This is not unlike the impact on our marine life we are seeing today.

On land, the PETM saw major shifts in plant and animal distributions, with many species migrating toward the poles to escape the heat, this is not something which will occur in present times as the poles continue to warm.? It also led to a temporary increase in mammal diversity, with the rapid evolution of new species adapted to warmer climates.

The PETM's temperature increase occurred over a few thousand years, whereas current global warming is happening over a few centuries, making it much faster and potentially more disruptive.? Unlike the PETM, today's warming is primarily driven by human activities, particularly the burning of fossil fuels and deforestation.

If current trends continue, we might see similar or even more severe consequences as during the PETM, including significant impacts on marine and terrestrial ecosystems, sea level rise, and more frequent extreme weather events.

Understanding past climate events like the PETM helps scientists predict potential future scenarios and hopefully allows us to open our minds to the urgency of mitigating current climate change impacts.

Looking at what happened during the Paleocene-Eocene Thermal Maximum period should be a grave reminder of the consequences that will arise from unchecked carbon emissions and global warming. The rapidity and scale of today's climate change, driven by human activities, presents an even more daunting challenge. Yet, unlike past events, we possess the knowledge and technology to alter our trajectory. The warnings from the IPCC report and the stark rise in CO2 levels are not just data points, they are urgent calls to action. It is imperative that we heed these warnings, prioritize sustainable practices, and commit to meaningful changes to safeguard our planet for future generations. The time to act is now, before we see events on a more devastating scale.

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