And, as one of the top six countries with the most room for new trees, Australia really could make a big difference if it gets on board.
The calculation of how much land can be afforested (about the area of the U.S. and China combined) doesn't include land now used by cities or cropland. Here, to explore this, Jean-Francois Bastin, Tom Crowther and colleagues leveraged a unique global dataset of forest observations spanning almost 80,000 forests, combined with the mapping software of Google Earth Engine, which they used to generate a predictive model to map potential tree cover worldwide under current conditions.
The land identified includes grazing land on which the researchers say a few trees can be planted and areas affected by things like logging and on-going burning.
As well as the existing trees, urban and agricultural regions, the researchers propose that Earth's ecosystems could hold an extra 0.9 billion hectares of tree cover that, upon maturing, could confiscate over 200 Gigatons of carbon, which equates to two thirds of manmade carbon emissions.
An area the size of the USA is available for planting trees around the world, and this could have a dramatic impact on climate change, a new study says. One of the study's lead authors estimated the cost at around $300 billion - to put that in context; the Australian government spent half that amount yesterday on widely criticised tax cuts.
Swiss scientists calculate that there's enough space to plant trees to cover 3.5 million square miles.
Pine trees are pictured on the Worldwide Day of Forests in the Landes woodland shut to Le Pyla, France March 21, 2019.
But the research paper, The global tree restoration potential, warns that the need for action is urgent: the climate is already changing and every year reduces the area of land that can support new forests.
The full study was published this week in the journal Science. Maybe send these links to your local MP, if you have some free time today. Crowther says tree planting is "a climate change solution that doesn't require President Trump to immediately start believing in climate change, or scientists to come up with technological solutions to draw carbon dioxide out of the atmosphere". The potential to grow trees alongside crops such as coffee, cocoa and berries - called agro-forestry - was not been included in the calculation of tree restoration potential and neither were hedgerows: "Our estimate of 0.9bn hectares [of canopy cover] is reasonably conservative", Crowther says.
The ETH Zurich researchers say six countries with the most space for new trees are Russian Federation, the United States, Canada, Australia, Brazil and China.
"If we act now, this could cut carbon dioxide in the atmosphere by up to 25 percent, to levels last seen nearly a century ago", said Crowther.
"This is by far - by thousands of times - the cheapest climate change solution" and the most effective, said study co-author Thomas Crowther, a climate change ecologist at the Swiss Federal Institute of Technology in Zurich.
It's not all about climate change, increased greenery would provide a host of benefits including more biodiversity, improved water quality and reduced erosion. However, this would be outweighed by losses in dense tropical forests, which typically have 90-100% tree cover. Trees remove more carbon from the air when they are younger, the study authors said. The newly filled out forests would be a huge boon to absorbing new emissions and the carbon pollution we've committed to the atmosphere.
As Earth warms, and namely because the tropics dry, tree veil is being misplaced, he noted.
Wimbledon 2019 order of play day seven
Also, No. 5 Kei Nishikori, 2017 Wimbledon semi-finalist Sam Querrey and Tennys Sandgren all reached the fourth round. Twitter was the place to be for King, who commented "Bravo!" on Murray and Williams' first-set win.
Turkey car blast may be terror-linked: Erdogan
Interior Minister Suleyman Soylu said two Syrians died at the scene while a third was taken to hospital with serious injuries. In May, Turkey sentenced the man behind the bombing on the country's border with Syria to life in prison.
'Dancing aunties' spark new Hong Kong protest
Large crowds were seen gathering outside the West Kowloon station which connects Guangdong city to other mainland destinations. The protests present the most severe challenge to Beijing and Hong Kong's leaders since the city's handover to China.
Another Powerful Earthquake Hits near Ridgecrest, California
The California Highway Patrol said portions of State Route 178 were closed because of rock slides, but they were quickly reopened. CalTech seismologist Lucy Jones said Friday both earthquakes are part of an ongoing sequence, of a "very energetic system".