Seeking to shore up enviro support and mollify free trade critics, Vice Pres. Al Gore announced yesterday that Pres. Clinton will sign an executive order requiring full environmental reviews of all new trade agreements. The order begins to put environmental concerns on par with business concerns in international agreements, a step that some environmentalists praised yesterday as a good start. Still, the executive order does not address environmental issues in other nations, and the environmental community is pressing the administration to push for reform of World Trade Organization rules and block any expansion of the WTO’s authority until the environmental impact of previous trade deals can be assessed. Meanwhile, a new national poll shows that most Americans are supportive of global trade but share labor and environmental concerns that have been raised by critics of the WTO.