The promises governments of several countries have been making to combat the climate crisis include "unrealistic" figures when they talk about reforestation and recovery of degraded ecosystems, a new report says. The document, anchored in a study led by the University of Melbourne, shows that these measures, combined, require 1.2 billion hectares of land to be complied with, an area larger than that of the United States.

Titled "The Land Gap", the report states that solutions for removing CO2 from the air that place too much emphasis on land use to mitigate the greenhouse effect are actually a subterfuge.The 20 scientists who sign the document say that governments' promises seek subterfuge to stop fighting the activities that actually cause global warming.

"In their climate promises, governments are prioritizing the planting of new trees to offset fossil fuel emissions rather than targeting deep cuts at all sources and protecting and restoring existing ecosystems," the document states.

The great contradiction pointed out by the researchers is that it makes no sense, from a planetary point of view, to let part of the forests be deforested in some places so that they can be replanted in others. This would cause a sharp rise in carbon emissions in this decade, which would be offset too late after several other decades.

The report was based on research led by scientist Kate Dooley, who investigated the NDCs (nationally determined contributions) of all countries that signed the Paris Climate Agreement. These are the documents in which governments detail how they intend to reduce their CO2 emissions.

"The land has a critical role to play in global efforts to lower the planet's temperature, but they are not a magical solution," she said at a press conference this morning. "Clearly, countries are exaggerating their land use commitments to avoid the hard work of drastically reducing fossil fuel emissions, decarbonising food systems and preventing the destruction of forests and other ecosystems," he added.

Detailing climate promises related to land use, Dooley and his co-authors say the most troubling point is that more than half of the area to be reserved for these solutions, 633 million hectares, would imply land use changes, which could affect global food production and compromise the way of life of smallholder farmers. The other 559 million in the account would be hit by restoring degraded ecosystems, but which are not now being used by agriculture.

Brazil, as the world's largest detonator, occupies a special position in the report because combating desmate needs to be the "number one priority" in climate policies on land use, scientists say. The report also points out that the protection of the right to land by indigenous communities and indigenous peoples is fundamental for the protection of areas of natural vegetation. These groups, scientists say, have been more effective than national governments in preserving natural ecosystems, which hold large carbon stocks.

"Governments' climate promises of carbon removal from the ground are unrealistic in terms of available land and impractical in terms of human rights tensions," the document's executive summary concludes.

Dooley and his colleagues criticize the overly focused promises to reduce "net" carbon emission values (calculating subtracting emissions removals) and little dedicated to bringing down the "gross" values of greenhouse gas production.

"Removing carbon from the ground is an important contribution to mitigation efforts, but it needs to be accompanied by rapid and deep cuts in fossil fuel emissions," they conclude.