A growing list of environmental rollbacks under U.S. President Donald Trump is raising questions about what they could mean for Canada, especially around the Great Lakes. Trump's administration has proposed eliminating funding for the Great Lakes Restoration Initiative , a U.S. program that supports efforts to clean up pollution, restore habitat and protect the world's largest freshwater system. The proposal is sparking concern on both sides of the border because the Great Lakes are shared by Canada and the U.S., and what happens on one side can eventually affect the other. A river does not stop flowing when it reaches an international boundary. Fish don't check their passports and migratory birds do not wait for permission before crossing into another country. Trump framed the string of rollbacks as a fight against what he calls excessive regulation, arguing that environmental rules have made it harder for Americans to afford cars, run businesses and produce energy. "My Administration has therefore taken historic action to reduce or remove these burdensome regulations and decrease the rising costs that consumers face," Trump said in a June memorandum . Trump has repeatedly described environmental regulations as a burden on American industry. In February, when the EPA announced it was eliminating the federal finding that greenhouse gases endanger public health and welfare, Trump called it the "single largest deregulatory action in American history" and described the Obama-era finding as a "disastrous" policy that had damaged the auto industry. The administration has also pushed to speed up environmental reviews for major projects, loosen restrictions affecting wetlands and water-related permits, expand coal development and roll back protections for endangered species. In September, 20 U.S. states and Washington, D.C., sued the Trump administration over new rules they say weaken the Endangered Species Act. One of the changes narrows the definition of what constitutes "harm" to protected species, potentially making it easier for development and fossil fuel projects to operate in critical habitat. The administration's proposed cuts to the National Oceanic and Atmospheric Administration, or NOAA, have also raised concerns about the loss of environmental data that Canadian researchers and communities rely on. Gail Krantzberg, Canada's lead investigator with the Global Centre for Climate Change Impacts on Transboundary Water said Canadians looked to the U.S. for key data on what's is happening in the Great Lakes. "A lot of Canadians relied on the extensive data," Krantzberg said in an interview with Yahoo News Canada . "The data is no longer available." 'Anything that the U.S. cuts back on ... means it gets into our water' Krantzberg has spent years studying the Great Lakes and the way water connects communities on both sides of the border. Her answer is straightforward. "We share over 300 rivers with the U.S.," Krantzberg said in an interview with Yahoo News Canada. "Anything the U.S. cuts back on in terms of regulation or restrictions means it gets into their water, which means it gets into our water." That doesn't mean every U.S. environmental rollback will create a problem in Canada, Krantzberg explains, but water is proving to be a key player. "Water flows across the boundaries," she said. Krantzberg is especially worried about the Great Lakes because pollutants can remain in the system for long periods of time. Dr. Gail Krantzberg speaks at an event. (Image courtesy: McMaster University) "The reason that they're so particularly susceptible is because the water stays in the Great Lakes for a very long period of time," she said. One example she points to is coal-fired power generation. The Trump administration has taken several steps to support the U.S. coal industry, including ordering agencies to prioritize the continued use of coal-fired power plants. The administration has argued coal is important for grid reliability and national security. "The increased interest in coal-fired utilities means the U.S. will burn more coal," she said. "When you burn coal, you emit mercury." That mercury can eventually make its way into waterways and fish, she explained, creating a problem that does not respect the international boundary. "Mercury gets into the lakes, it deposits locally, and it gets into the fish," Krantzberg said. "And if you're a subsistence fisher, like an Indigenous fisher, for example, you're eating that." "And we can't stop that mercury from coming into our side of the Great Lakes." 'It's not a Canada ecosystem' The border does not stop wildlife either, she explained.

"Think about the salmon that crosses the border going from the United States into Canada to spawn," Krantzberg said. "They go from the U.S. into Canada, back into the U.S., and so whatever goes downward in terms of degraded habitat means those fish and wildlife will not be able to reproduce successfully." The result is a shared ecosystem that cannot be neatly divided into two national halves, said Krantzberg. "It affects the entire ecosystem, which is a Great Lakes ecosystem," she said. "It's not a Canada ecosystem. It's not a U.S. ecosystem." Migratory birds are another example. Krantzberg pointed to Point Pelee and Lake Erie, where Canada and America meet around one of the most important migratory corridors in North America. "If you start trashing the waters there, then this whole migratory bird movement can very well start coming through that corridor," she said. Canada has agreements. But it cannot control U.S. policy Canada and the United States have spent decades building systems to manage their shared waters, Krantzberg said. The Great Lakes Water Quality Agreement was first signed in 1972 and updated in 2012. It is a legally binding Canada-U.S. treaty covering issues including toxic chemicals, nutrients, invasive species, habitat, groundwater, climate change and science. Krantzberg said the decades of cooperation remain important, but they cannot force Washington to adopt environmental policies that it does not want. "If the U.S. turns its back on this agreement, there's nothing that Canada can really do to stop that from happening," she said. The agreement provides a framework for cooperation, but Canada cannot regulate what happens inside the United States. "If there's an increase in pollution on the U.S. side because of deregulation of various corporate inputs or industrial inputs, that gets in the water," Krantzberg said. "We can't stop the U.S. EPA from deregulating. Canada cannot stop that." That leaves political pressure and continued cooperation between governments, communities and environmental groups as some of the tools available to Canada. Horizontal profile image of two Common Loons (Gavia immer) swimming on a calm northern Ontario lake in Temagami at sunset. Krantzberg pointed to the network of governors, premiers and mayors around the Great Lakes as key players to changes in federal policy. "There's something called the Great Lakes Restoration Initiative, (GLRI.) It's around $400M a year to compensate for historic damage, and it's been hugely, wildly successful," Krantzbert said. "When Trump came around, he put in his budget that he was zeroing that out. Eight of them said, 'No, you're not.'" 'Nobody owns the waters' For Canadians wondering what action they can take as Trump walks back environmental protections, Krantzberg's answer comes back to stewardship. "Nobody owns the waters. Everybody owns the waters." "The waters are shared, and the waters move freely across the entire boundary. Freely," Krantzberg added. That shared responsibility becomes critical as the two countries move in different environmental directions. Krantzberg urged Canadians to make their concerns known to political leaders, while also paying attention to what happens closer to home. "You write to the prime minister's office. You write to your member of Parliament and your member of provincial Parliament, and you raise your concerns and have your voice heard," she said. "At the same time, you do things that are responsible as a steward of these waters on your own property, because cumulatively, everything matters." For Krantzberg, the question comes back to water itself and what Canadians want to leave behind for the next generation. "Do you really want your kids to drink that?"