At an estimated 7.2 billion hectares, carbon dioxide emitted from fossil fuel use is the largest contribution to humanity’s ecological footprint (more than double its nearest competitor, cropland). Indeed, of all the impacts we have on the planet, carbon dioxide is the only one that is identifiably and totally waste; and its destructive effects are well documented (global warming). If we could magically remove this impact, natural systems could easily support us and other species – humanity would be below the maximum sustainable footprint (currently 9.5 billion hectares).
If current trends continue, then by the early 2020s the footprint from carbon dioxide emissions alone will equal the maximum sustainable footprint (at that time, due to projected increases in bio-productive land, about 10.3 billion hectares). It is perhaps no coincidence that by then our population will have passed its peak.