Humans have increased atmospheric CO 2 concentration by more than a third since the Industrial Revolution began. This is the most important long-lived forcing of climate change. Methane.
Buy Forever stamps online directly from USPS. The current Forever stamp value is 49-cents - the current First-Class Mail one-ounce rate.
Features. 1  Postage starts at $1.20. 2  Our most affordable international service. 3  Can be used for postcards, letters, and large envelopes. 4  Eligible for flats up to 4 lbs and up to $400 in value. 5  Global Forever stamp available. 6  Delivery varies by destination.