Commentary

Climate policy should aim to limit the rate of warming, as well as setting a cap on total allowable emissions.

In their efforts to make climate information more useful for adaptation decisions, scientists will need to be clear about the limits of climate prediction.

Humanity must learn to live within a stable Holocene environment, but the boundary limit for land use depends on more than the amount of surface covered.

Ocean acidification has impacts other than simple changes in pH, and these may need boundaries too.

Five per cent is a reasonable limit for acceptable ozone depletion, but it doesn't represent a tipping point.

For nitrogen deposition as for other pollution, waiting until we approach the limits of environmental degradation merely allows us to continue our bad habits until it's too late to change them.

Setting a limit on long-term atmospheric carbon dioxide concentrations merely distracts from the much more immediate challenge of limiting warming to 2 °C.

A global limit on water consumption is necessary, but the suggested planetary boundary of 4,000 cubic kilometres per year is too generous.

A boundary that expresses the probability of families of species disappearing over time would better reflect our potential impacts on the future of life on Earth.

National targets give virtually no chance of constraining warming to 2 °C and no chance of protecting coral reefs.

An oft-forgotten source of food security and livelihoods, fisheries must be included in ongoing discussions of how the world’s most vulnerable can adapt to climate change.

Emissions targets must be placed in the context of a cumulative carbon budget if we are to avoid dangerous climate change.

Policymakers must start to view mass migration as a form of adaptation so that the global response to climate-induced migration is one of facilitation rather than neglect.

Despite some recovery of the Arctic summer sea ice this year, the signs suggest the transition to a seasonally ice-free Arctic Ocean is underway.

The notion that we need nuclear power to address climate change does not reflect the realities of the marketplace or rapid new developments in energy technology.

Climate researchers must begin to bridge disciplinary divides — and institutions must begin to reward them for it.

Both national and global climate policy must redirect its focus from setting a price on carbon to promoting the rapid deployment of clean technologies.

Both emissions reduction and adaptation will need to be much stronger than currently planned if dangerous global impacts of climate change are to be avoided. June's UN talks in Bonn and July's G8 summit present opportunities for world leaders to face this challenge.

Why are harlequin frogs disappearing across the American tropics? A resifting of the evidence backs up the conclusion that global warming is a key conspirator in the losses.