Think of it as a half life. Suppose every piece of macro plastic sheds 0.1% of its mass yearly due to weathering, and suppose that there are 10 billion tons of

Think of it as a half life. Suppose every piece of macro plastic sheds 0.1% of its mass yearly due to weathering, and suppose that there are 10 billion tons of plastic waste. We calculate 1. The half life 2. The microplastic production rate --------- import math # Define the rate at which macroplastic turns into microplastic per year rate_per_year = 0.1 / 100 # 0.1% # Half-life formula for exponential decay: T_half = ln(2 )/ decay_constant # Here, decay_constant is the rate_per_year half_life = math.log(2 ) / rate_per_year half_life # 693.1471805599452 years # Initial amount of macroplastic in metric tons initial_macroplastic = 10 * 10*9 # 10 billion metric tons # Annual production of microplastic is 0.1% of the initial macroplastic per year annual_microplastic = initial_macroplastic * rate_per_year annual_microplastic # 10 million metric tons. ------------- We produce 350 million tons of plastic waste a year. Over 30 years that's 10 billion tons. The .1% weathering rate was conservative. So weathering likely creates more than 10 million tons in microplastic annually. And will probably do so for at least a couple hundreds of years.