Sunday's forecast calls for high temperatures just above 60 degrees. It's shaping up to be a nice, if slightly cool, Earth Day in Philadelphia. But warmer weather has been slow to arrive this year, with temperatures dipping below freezing as recently as two weeks ago. The high on the first day of spring was just 35 degrees – nearly 20 degrees below the historical average.

Cooler temperatures make for disappointing spring days and even disappointing claims from climate-change deniers who say the fact that it's cold one day means climate change is a hoax. President Trump, never one to shy away from weighing in on a topic he fails to understand, actually wished for more global warming in a tweet during a cold spell last winter. Trump and others are confusing a stretch of cold weather in one area with a continuously warming climate around the globe.

They do not understand, or are willfully ignoring, the big picture.

On Earth Day, it's crucial that we look beyond the weather forecast and take a closer look at our environment and the big picture. It's a chance to consider how our planet has changed and what it will look like in the future. The picture is not encouraging. The fact is, temperatures around the world are rising, and man-made climate change is doing irreparable harm to our environment and our planet's future.

Take methane emissions, for example. Methane is the second-most common greenhouse gas, with 86 times the warming effect of carbon dioxide over a 20-year period, according to the United Nations' Intergovernmental Panel on Climate Change. Looking to the past shows us that methane levels in our atmosphere have doubled with the rise of industry. More than 60 percent of methane emissions today are from man-made sources, with oil and gas production as a leading cause along with agriculture and landfills.

Looking to the future, continuing leaks from natural gas operations and other man-made global-warming emissions will exacerbate the increase in temperatures. The National Climate Assessment estimates world temperatures could rise by 8 degrees by 2100. This will cause more unpredictable and dangerous weather – in addition to higher death rates, more wildlife extinction, increased air pollution, and rising sea levels. The future of our planet looks grim – unless we take bold and immediate action.

Earth Day is the perfect opportunity to reflect on our environment and our role in protecting it. But as climate change has shown, looking at one specific day doesn't really reveal our true impact on the environment. It's the actions we take every day, year after year, that will determine the future of our planet.

Even simple actions, over time, can have a monumental impact. Find a recycling bin. Carpool with a friend. Buy a reusable water bottle. Unplug appliances. Learn more about climate change. Contact elected officials. Stay informed. These everyday actions are more powerful and necessary than ever.

Joseph O. Minott is executive director and chief counsel of the Clean Air Council.