As Brazil’s government steps back from Amazon conservation, the urgent need for stronger protection has been made more apparent by a new data map that highlights the knock-on effect of the forest’s capacity to absorb carbon, regulate temperatures and sustain life.

Launched on Tuesday, the Silent Forest project assesses the extent and impact of forest degradation – a largely man-made phenomenon that is less well-known than land clearance, but is seen by scientists as potentially more of a problem for the climate and biodiversity.

Forest degradation is the thinning of tree density and the culling of biodiversity below an apparently protected canopy – usually as a result of logging, fire, drought and hunting.

It is more difficult for satellites to monitor than deforestation (the total clearance of foliage) because the canopy – when viewed from above – appears uninterrupted, even when many of the plants underneath have been cut down or destroyed and the habitat of many species has disappeared.

As a result, it is harder to tackle and has long been overlooked by policymakers, even though scientists warn it may have a bigger impact on biodiversity loss and carbon emissions.

To draw attention to the trends and the risks, the Silent Forest “disturbance map” highlights the black spots of forest degradation (particularly prominent near Santarem, Sinop and on the border of Pará and Maranhão states), as well as areas affected by roads, logging and forest fires, which tend to cluster together as a result of (often illegal) human activity.

During the 2015-16 El Niño, fires affected 38,000 sq km of Brazilian Amazon – more than five times the area classified as deforested. On other land, loggers cut deep under the canopy to remove the most valuable timber and swaths were bisected or fragmented by roads.

This creates a vicious circle because degraded land is drier and results in lower rainfall in surrounding areas, which increases the vulnerability to arson and accidental fire.

“It is terrifying to see the Amazon degraded to this extent,” said Jos Barlow, a scientist at Lancaster University and one of the authors of a key study being used for the data visualisation. “Every time we go to field, we measure plots and find the situation is far far worse than before but nothing is being done about it.”

He and the other scientists behind the data visualisation hope the new tool will guide policymakers to tackle the multiple causes of forest degradation.

Thiago Medaglia, coordinator of the Silent Forest platform, said: “The data visualization from scientific studies is an important step in the struggle for forest conservation. Now, it is possible not only to visualize the impacts of deforestation in the Amazon, but also those of degradation.”

They have also added information on biodiversity loss to widen the potential audience. Bird lovers, for example, will be alarmed to discover that some of the worst wildfires last year occurred in the habitat of the highly endangered black winged trumpeter on eastern Amazon. The species – which numbered only 100 or 200 individuals – is now considered the most likely to go extinct in the near future.

Last year, an international team of researchers found that areas in Pará state with the highest levels of protection still lost between 46% and 61% of their conservation value as a result of degradation.