Pre-industrial emissions are still having a tremendous effect on global temperature, according to an Environmental Research Letters journal report.
Researchers from the Carnegie Institution for Science have found that pre-industrial emissions are affecting global temperature. They found that pre-industrial emissions from land use changes - converting forest land into agricultural land for cultivation - are responsible for about nine per cent of the increase in today's global temperature.
Industrialisation had released huge amounts of carbon dioxide into the atmosphere, which has caused global warming. But now, researchers have found that deforestation for agricultural purposes in the pre-industrial era has also contributed to an increase in Co2 and the carbon emission still has a major effect on global temperature.
"The relatively small amounts of carbon dioxide emitted many centuries ago continue to affect atmospheric carbon dioxide concentrations and our climate today, though only to a relatively small extent," said Julia Pongratz, researcher at the Carnegie Institution for Science.
"But looking into the past illustrates that the relatively large amount of carbon dioxide that we are emitting today will continue to have relatively large impacts on the atmosphere and climate for many centuries into the future," she added.
Scientists discovered this while analysing few climate models from around the world. To know the exact Co2 emission, scientists calculated the amount of Co2 released during the pre-industrial period. They claimed pre-industrial pollution was mostly caused by south and East Asia. China and India alone account for half of the population growth between 800 and 1850 AD.
The researchers' model suggests that 20 to 40 per cent of China and India's entire history of CO2 emissions comprises pre-industrial emissions related to this population growth. The models showed that these emissions are still having a detrimental effect on our climate today.
"Accounting systems are not natural facts, but human inventions," said Ken Caldeira, researcher at the Carnegie Institution for Science, in a statement. "Once an accounting system is defined, it becomes a matter of scientific investigation to determine what numbers should go in the ledger, but broader questions of who is responsible for what and who owes what to whom are judgments that lie outside the scope of science."