Indo-Asian News Service: During the week of April 6 to 12, average carbon dioxide (CO2) levels touched 404.02 parts per million (ppm), the highest-ever in recent human history - and 15 percdent above the levels of 350 ppm scientists say is ideal for Earth. The months of February, March and April had monthly average CO2 levels higher than 400 parts per million (ppm), the first time in recorded history all three months have reached such levels, according to the keystone Mauna Loa observatory in Hawaii. These rising levels...