Yes, Obama's environmental efforts will probably be wasted now that Trump has been elected. Trump does not seem to be very interested in environmental efforts and has even been known to deny the reality of global warming. In addition, Trump has financial interests that are in conflict with environmental protection efforts.
Trump has said many things about reversing what Obama has accomplished. I am not completely sure that he really meant that about everything he talked about, but he is sure to undo many. I see climate change and environmental issues as one of the things that Trump will ignore and reverse, which is unfortunate to our future generations.
With any luck, Obama's environmental efforts be wasted now that Trump has been elected. Obama has bought the myth of an endangered climate and environment hook, line and sinker; even though everything he claims is based on questionable science at best. God willing, this nonsense is put to a stop.
Even though Obama's efforts are contrary to Trumps, many of the good things that Obama did will leave a legacy. Many of Michelle Obama's efforts to teach kids to eat healthy and be physically active will continue. He also made progress in the areas of civil rights, and becoming the first black President. Those things will never be undone.