Nowadays world faces crisis caused by growing energy demand. Threat of climate change caused by the increased emission of CO2 from burning of fossil fuels exerts pressure on wider use of renewable energy resources. It is believed that one of important resources of renewable energy are biofuels. In the paper we present that in the most cases it is not true. Wide use of biofuel, especially in European Union, poses threat to sustainable development of today’s world. It is going to be presented that the production of biofuels from agricultural crops is, in many cases, unsustainable due to the fact that it reduces the access to food by devoting cultivatable land to crops designated for the production of biofuels. What is more, it has also negative influence on the environment, namely it reduces biodiversity, pollute water and, what is curious, not in all cases the use of biofuels leads to the reduction of CO2 emission.
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.
The global fluxes of carbon in the ecosystem of Earth, with particular attention drawn to the cycle of CO2 were characterised. The sequestration of carbon dioxide in the biomass of plants, especially the ones which can be cultivated as catch crops is described. It was shown that the cultivation of catch crops may play an important role in the mitigation of CO2 emissions.