Know better. Do better.

Climate scientists for years have urged governments and businesses to slash climate-changing emissions, with limited success.

On Monday, they changed tack and appealed directly to everyone on the planet to seize a dwindling chance to limit global warming to 1.5 degrees Celsius, or risk fundamental harm to both people living today and their descendants for thousands of years.

With easy-to-grasp graphics showing the scale of coming heatwave risks likely to affect everyone from babies to retired people within their lifetimes, the U.N.'s Intergovernmental Panel on Climate Change (IPCC) warned "there is a rapidly closing window of opportunity to secure a liveable and sustainable future for all".

It showed "high" or "very high" confidence by scientists about the scale of coming risks and emphasized that shifting to clean energy made sense - for health and well-being reasons - even for those relatively unconcerned about climate change.

For too long, “we at all levels - governments, communities, individuals - have made climate change somebody else's problem" - a reality that needs to change, said Peter Thorne, one of the authors of the new summary report of climate science and a geography professor at Ireland's Maynooth University.

Water risks also need more attention, scientists said this week as a major U.N. water summit gets underway in New York.

Human activities - from destroying forests to burning gas, oil and coal for energy - are disrupting the rainfall the world depends on, fuelling huge economic, health and social stability threats, they warned.

"We've built our economies on the assumption we can rely on precipitation," said Johan Rockström, director of the Potsdam Institute for Climate Impact Research and co-chair of the Global Commission on the Economics of Water.

But "what we're finding is climate change and land use change is shifting that very significantly," he said.

Deforestation, for instance, is shifting the flows of water vapour that rise from forests like the Amazon, causing worsening drought in distant places that depend on those flows.

Protecting water security in the future will require taking a much wider look at what has often been thought of as a local or regional problem, scientists said.

"Behind food production, behind energy, behind all the SDGs (Sustainable Development Goals), there is a volume of freshwater that powers the delivery of that service," Rockström said. "Right now we just take it for granted".

But changing what needs to be changed - swiftly - is rarely easy.

A bold plan by Colombia's president to phase out the country's reliance on oil and coal revenue as part of its clean energy transition will likely take decades, economists warned, particularly amid uncertainty over whether efforts to scale up alternatives - such as boosting tourism and agriculture - can work.

For now, the government has not yet put a ban on new oil exploration contracts into writing, or into its four-year development plan, unveiled in February.

"The decision to replace fossil fuel exports is a responsible one .... no one said it would be easy," said Giovanni Pabón, energy director at Transforma, a think-tank on climate action.

But researchers at the World Resources Institute have some ideas about how Colombia and other emerging economies could get started now on a shift away from oil and gas, while helping the workers and communities who might lose out. 

See you next week,

Laurie