Climate future looks bleak

The climate continues to change, causing fiercer wildfires, stronger storms and displacing coastal and island communities all over the world. Dr Anjani Ganase reviews the IPCC sixth Assessment Report and looks at the slippery slope that we on small islands face. The world as we know it is changing rapidly.

The Intergovernmental Panel for Climate Change (IPCC) was established in 1988 by the World Meteorological Organization (IMO) and UN Environment Programme (UNEP) for the purpose of reviewing and compiling climate-related research to advise governments on the impacts of climate change.

Considering the global impact of climate change, the IPCC body consists of 193 global members and thousands of contributing scientists across many countries.

The IPCC scientists volunteer their time to collate all information on the drivers of climate change, future projections, understanding the global and regional impacts, as well as studies on mitigation and adaptation strategies. The report requires a transparent review process where experts and governments can review and work towards a scientific consensus with global acceptance.

In 1990 the first assessment report was released; 30 years later, the IPCC released its sixth assessment report, Working Group One – which focuses on the physical science of climate change. The other two working groups include Impacts, Adaptation and Vulnerability, which assesses the vulnerability and adaptability of natural and human systems to climate change, and Mitigation and Climate Change, where scientists review the methods for reducing and removing greenhouse gases from the atmosphere. Both working groups will be released next year.

In this report, the IPCC is now able to present observable changes in the climate over the past 40 years to validate previous climate projections and fine-tune future projections. Scientists can now pinpoint the timeline of climate-change impacts and determine when human activities began to significantly alter our climate.

We can also track our progress, or the lack thereof, based on the pledges made by global leaders during the Paris Agreement in 2015. Leaders from around the world pledged to curb the emissions of greenhouse gases in order to limit global warming to below 1.5 to two-degree temperature rise above industrial levels by the end of the century.

Six years later, our current policies have us on track for a three-degree global temperature rise by 2100, and we are already one degree Celsius above pre-industrial conditions, with visible environmental consequences.

In this report, it is very clear that the hopes to limit to a 1.5 C temperature rise seems in vain, unless there is a radical reduction to a global net zero of greenhouse gases by 2050.

Considering that the world’s economies are reeling from the covid19 pandemic, with no large-scale climate adaptation mechanisms in sight for TT, this is a major concern.

This is especially dire for small island nations, which will already suffer significantly at 1.5 C above, as highlighted by the IPCC Special Report: at global warming of 1.5 C there is significant loss of biodiversity. For coral reefs, a 1.5 C warming means 70-90 per cent loss by 2050, a two-degree rise means the loss of all our reefs.

Accelerated sea-level rise and the combined effects of extreme storm events (hurricanes) will cripple us. Many of our neighbours have already suffered such experiences. Remember 2019, when category five hurricane Dorian sat over the Abaco Island of Bahamas, unleashing its fury. The island was submerged by the water being dumped. The infrastructure of the island was wiped out. Seventy lives were lost, and to this day, over 200 people are still “missing.”

Here are some examples of what we can confirm based on the observations over the last 50 or so years. Human activities have been the major driver in the increase in the global mean temperature over the last four decades (since 1980). Global surface temperature is on average one degree higher compared to the last century (before the 1900s) and the rise in temperature is much greater on land compared to the ocean. The temperature rise in both places has already had observable and severe consequences for the environments and ecosystems.

Warming conditions have resulted in a pole-ward shift of heavy rainfall (precipitation) since the 1980s.

This means that higher latitudes have become more at risk of tropical cyclones – areas with infrastructure not equipped to withstand hurricanes. Remember, Hurricane Sandy hit New York City in 2012. Cyclones have become stronger, with more category three to five storms being observed in the last 40 years. Meanwhile, at the poles, human-influenced global warming has resulted in the retreat of glacier ice since 1990s, with significant ice loss in the Arctic and on Greenland. Heat waves have become more frequent since the 1950s, while cold extremes have become less common. Globally, more people died from extreme cold temperatures, but there is an increase in the mortality rate at high temperatures, especially in Europe and the Pacific.

In the ocean, global warming has affected the upper layers of the ocean since the 1970s. As a result, marine heatwaves have also become more frequent since the 1980s, reflected in mass coral-bleaching events around the world.

Carbon emissions have also driven significant acidification in the open ocean and oxygen levels of the ocean have declined in specific regions around the world. Global mean sea-level rise was observed to double from the 1900s-1971 (1.3 mm/year) to 2006-2018 (3.7 mm/year).

Without significant and drastic reduction in greenhouse gases, we are in for more warming impacts – with consequences to ecology, and society – along with climate-related environmental tipping points. Other tipping points to look out for: ocean and land carbon sinks will become depleted either by being saturated with carbon dioxide (in the ocean), or the result of land-use changes such as the clearing of forests (especially the Amazon rainforest).

A new study has already shown that parts of the Amazon are no longer carbon sinks. Without these sinks, the rate of global warming will increase. The ice sheet collapse is another tipping point, resulting in the slippage of large ice sheets into the ocean. This will add to sea-level rise and decrease ocean salinity. It is also likely that there may be an abrupt change in the ocean circulation, with consequences to weather and ecology. It is very likely that the Atlantic Meridional Circulation will weaken by the end of the 21st century, in 80 years, regardless of our carbon trajectory.

In the Caribbean, it is very likely we will continue to observe a decline in rainfall during the months June to August. Warming conditions will result in evaporation of rainfall and drought conditions that affect the agricultural sector and natural forest reserves. Marine heatwaves will continue to increase in frequency and severity.

In Tobago, annual severe bleaching events are projected to occur from 2042, based on current projections. Sea-level rise, combined with more severe extreme storm events, will likely exacerbate the destruction of coastal habitats and communities. Saltwater intrusion further inland will likely degrade coastal vegetation as well as contaminate freshwater systems.

There is a lot of uncertainty in our future, since not much research or environmental observation and high-resolution climate modelling has been conducted for small islands.

Is covid19 the training ground for climate-change disaster response? Mitigation and adaptation measures are now the only way to combat climate change. We have rapidly warmed the planet at an unprecedented rate over the last 170 years, compared to the last 2,000 years, using fossil fuels. We also managed to accelerate the warming in the last 50 years, since the 1970s.

With such dramatic shifts in environmental conditions, we have already witnessed significant loss in biodiversity and will continue to lose biodiversity at an alarming rate with consequences to us. The compounding impacts of worsening land and marine heatwaves, along with severe weather events, are already devastating places around the world.

Climate change has affected every inhabited and uninhabited place on the planet. Scientists have confirmed that the current and future projected emissions and its impact to the planet will be irreversible for the next millennia, as carbon emissions released into the atmosphere will remain for thousands of years.

In our lifetime, we have changed things permanently; this trajectory is the new normal.

For more info: check out all the reports here: https://www.ipcc.ch/