419.28 ppm: tracking weekly climate news

Welcome to our regular segment on climate news stories you might have missed. The title refers to the daily average global concentration of carbon dioxide within the Earth’s atmosphere in parts per million (ppm) – meaning that for every million air particles, currently about 419.28 of them are CO₂.

The second section of the Intergovernmental Panel on Climate Change (IPCC) report – Working Group II – was released earlier this week, examining the world population’s vulnerability to climate change. Here’s five key take-aways from it that you might have missed.

1. Dire news for ecosystems

Climate change has already caused extensive damage and irreversible losses in the Earth’s ecosystems, from terrestrial to freshwater and marine environments. But according to the new IPCC report, the extent and magnitude of these impacts are larger than previously estimated.

In Australia, climate trends and extreme events have combined with exposure and vulnerabilities to cause major impacts for many natural systems, and the report has very high confidence that Australia’s ecosystems are experiencing, or are at risk of, irreversible change. In particular, marine impacts from ocean warming and marine heatwaves have already resulted in a major loss of temperate kelp forests and extensive coral bleaching events.

“We found that exceeding 1.5°C warming for several decades would result in severe and potentially irreversible impacts, especially in nature,” says Gretta Pecl, professor of marine ecology at the University of Tasmania. “We would see species extinctions and losses of entire ecosystems, such as tropical coral reefs and temperate kelp forests.”

2. The most vulnerable people are most affected

The climate crisis is particularly affecting the world’s most vulnerable people, which is contributing to humanitarian crises. There’s already human displacement in all regions of the world, with those living in small island states especially at risk.

Flood- and drought-related acute food insecurity and malnutrition have increased in Africa, Central and South America, on small islands and in the Arctic. In Australia, climate impacts disproportionately affect the welfare of impoverished and vulnerable people because they lack the resources needed to adapt.

“To achieve sustainable development for all, mitigation measures and adaptations to climate change need to be integrated and undertaken in equitable and just ways,” says Dr Andrew Constable, applied systems ecologist in the Centre for Marine Socioecology (CMS) from the University of Tasmania.

“Australia already has the tools and expertise available for reducing risks and supporting climate resilient development. This strong foundation can be used to engage with everyone, including Indigenous peoples, to implement what is needed over the next decade.”

3. Cities are hotspots for impacts and risk

The impacts of climate change in cities, where more than half of the world’s population lives, was assessed in detail in the report. The authors found that people’s health, lives and livelihoods, and the property and critical infrastructure in cities, are being increasingly adversely affected by hazards stemming from climate change – heatwaves, storms, drought and flooding, and slow-onset changes such as sea-level rise.

“Together, growing urbanisation and climate change create complex risks, especially for those cities that already experience poorly planned urban growth, high levels of poverty and unemployment, and a lack of basic services,” says Debra Robert, IPCC Working Group II co-chair.

It’s not all bad news for cities, according to Robert, as they provide unique opportunities for playing a crucial part in the solution to climate change.

“Cities provide opportunities for climate action. Green buildings, reliable supplies of clean water and renewable energy, and sustainable transport systems that connect urban and rural areas can all lead to a more inclusive, fairer society.”

4. Nature provides an opportunity for reducing climate risks

A key method for securing a liveable future is through the safeguarding of biodiversity and ecosystems, with the report providing new insights into the potential for nature to not only reduce climate risks but also improve people’s lives.

“Healthy ecosystems are more resilient to climate change and provide life-critical services such as food and clean water,” says Hans-Otto Pörtner, IPCC Working Group II co-chair.

“By restoring degraded ecosystems and effectively and equitably conserving 30% to 50% of Earth’s land, freshwater and ocean habitats, society can benefit from nature’s capacity to absorb and store carbon, and we can accelerate progress towards sustainable development, but adequate finance and political support are essential.”

5. There is a narrowing window for action

The window for action in mitigating climate change is narrowing. Already challenging at current warming levels, our ability to develop climate resilience will become more and more limited if global warming exceeds 1.5°C, and in some regions will be impossible if it exceeds 2°C.

“Although projected impacts at 1.5°C of warming are worrying, at higher levels of warming, potential impacts are worse,” says David Schoeman, professor of Global-Change Ecology at the University of the Sunshine Coast. “The greater the warming and the longer it lasts, the less chance there is of reversing the resultant impacts in the future.”

Near-term actions that limit global warming to close to 1.5°C would substantially reduce projected losses and damages related to climate change in human systems and ecosystems. The report highlights the urgency for climate action in the coming decade, including adequate funding, political commitment and partnership to lead to more effective climate change adaptation and emissions reductions.

“It emphasises the urgency of immediate and more ambitious action to address climate risks,” says Hoesung Lee, chair of the IPCC.

“Half measures are no longer an option.”