Between 1850 and 1985 approximately 155 billion metric tons of carbon was added to earth's atmosphere and climate became about 0.5 degrees C warmer, indicication of greenhouse effect. It is evaluated that doubling carbon dioxide in atmosphre would result in the average global temperature increase of 4-5 degrees C. Future amount A of carbon dioxide in atmosphere per parts per million is at times evaluated using formula A = a + ct + ke^rt. Where a, c, and k are constants, r is percentage increase in emission of carbon dioxide and t is time in years. With t = 0 representing to 1990. Assume it is evaluated that in year 2070, A will be 800 if r = 2.5% and A will be 560 if r = 1.5%. If, in 1990, A = 340 and r = 1%, determine year in which amount of carbon dioxide in atmosphere will have doubled.