Climate change is accelerating and intensifying across every region of the planet, bringing with it increases in rainfall, flooding, drought, heatwaves and sea levels that are already having significant implications for economies around the world.

That is the stark consensus of the world's leading climate scientists in a landmark United Nations report Monday, which offers the clearest picture yet of both the scale of global warming already being experienced and the likely impacts of further temperature rises that are set to play out over the coming decades.

The report concludes that the world's average surface land temperature currently stands at around 1.1 degrees Celsius above pre-industrial levels and is likely to reach 1.5 degrees C — the optimal target set out in the Paris Agreement — within the next 20 years regardless of potential actions taken to slash greenhouse gas emissions in the meantime. It also stresses that human actions are "unequivocally" the primary driver of the escalating climate crisis.

Due to human activity — largely the burning of fossil fuels — concentrations of CO2 in the atmosphere are higher than at any time in the last 2 million years, with concentrations continuing to increase in 2020 despite the temporary dip in annual global emissions that resulted from the COVID-19 pandemic, according to the report.

As a result, climate change is already affecting every inhabited region on Earth, and impacts such as sea-level rise, ocean acidification and permafrost melt are inevitable and near-irreversible, leaving only their extent open to question. Some of these impacts are now thought to be irreversible within timespans stretching to thousands of years.

The report stresses that unless there are immediate, rapid and large-scale reductions in greenhouse gas emissions over the next two decades, then the goals of limiting average temperature increases this century to 1.5 degrees C or even 2 degrees C above pre-industrial levels will be beyond reach, the scientists warn, leading to warming scenarios that could have catastrophic impacts for all ecosystems and societies.

Read the full article about irreversible climate impacts by Michael Holder at GreenBiz.