Question

Which statements about global climate change are scientific statements supported by evidence?

A) All things must live in harmony with nature, or nature will act to restore the balance.

B) Atmospheric concentrations of CO₂ have increased dramatically over the last century.

C) High atmospheric concentrations of CO₂ are linked to warm periods in the history of the Earth.

D) B and C

E) All of the above

Answer 1

ANSWER: Option (D)

It is because;

The planets average surface temperature has risen about 1.62 degrees Farenheat (0.9 degree Celsius). Since the late 19th century, a change driven largely by increased carbon dioxide and other human made emissions into the atmosphere. The heat trapping nature of carbon dioxide and other gases was demonstrated in the mid 19th century. Their ability to affect the transfer of infrared energy through the atmosphere is the scientific basis of many instruments flown by NASA. There is no question that increased levels of greenhouse gases must cause the earth to warm in response.

In nature carbon dioxide is exchanged continuosly between the atmosphere, plants and animals through photosynthesis , respiration and decomposition and between the atmosphere and ocean through gas exchange, A very small amount of carbon dioxide (roughly 1% of the emission rate from fossil fuel combustion) is also emitted in volcanic eruptions. this is balanced by an equivalent amount that is removed by chemical weathering of rocks.

The CO₂ level in 2019 was more then 40% higher than it was in the 19th century. most of these CO₂ increased has taken place since 1970, about the time when global energy consumption accelerated. Measured decreases in the fraction of other forms of carbon (the isotopes ¹⁴C and ¹³C) and a small decrease in atmospheric oxygen concentration shows that the rise in CO₂  is largely from combustion of fossil fuels (which have low 13C fractions and no 14C). Deforestation and other land use changes have also released carbon from the biosphere where it normally resides for decades to centuries.