National salad chain Sweetgreen said it will add steak to its menu, but reassured its environmentally conscious customers that it will offset its carbon footprint by putting in place strategies to reduce emissions, according to a report. The restaurant chain, founded in 2007, that offers a variety of salads and bowls said it will become carbon neutral by 2027 despite the announcement Tuesday that it will include a caramelized garlic steak protein plate to its menu. Beef production is the largest agricultural source of greenhouse gases globally and emits huge amounts of methane into the atmosph…