Carbon dioxide fluxes between ecosystems of the Earth are presented. It was shown that intensifying its absorption of terrestrial ecosystems by 3.2% would prove sufficient to neutralize carbon dioxide emissions from the combustion of fossil fuels and cement production. It was shown that Polish forests absorb 84.6 million tons of CO2/year, that is 26% of emissions from fossil fuel combustion and cement production, while agricultural crops absorb 103 million tons of CO2/year. Total carbon dioxide sequestration by forests and agricultural crops amounts to 187.5 million tons of CO2/year, which is tantamount to 59% of emissions from fossil fuel combustion and cement production. Forestation of marginal soils would further increase carbon dioxide absorption in Poland by 20.6 million tons of CO2/year. Moreover, if plants were sown in order to produce green manure - instead of leaving soil fallow - sequestration could still be boosted by another 6.2 million tons of CO2/year.