In 1992, I attended an event that filled me with hope.

Canada and the rest of the world had just signed a climate change treaty at the United Nations Earth Summit in Rio de Janeiro.

I remember being optimistic that the world could come together to fight the greatest threat to our planet and our own survival. We had done it before in overcoming other threats, like defeating Nazism in Europe and beating back horrific diseases like polio.

When Canada signed the UN Framework Convention on Climate Change (UNFCCC) treaty, we had not yet begun to experience the full consequences of climate change. There were no news reports of starving polar bears in the Arctic, the mountain pine beetle had not yet turned British Columbia’s forests crimson, and we weren’t facing a rapid increase in infectious diseases, like Lyme disease, that are exacerbated by warming temperatures.

But climate change is now affecting people and places all over the planet, from the most remote tropical rainforest to the urban parks where many of our kids play.

And scientists tell us that some changes, like melting sea ice in the Arctic, are happening much faster than any computer model had predicted.

Though the 1992 UNFCCC treaty set no mandatory limits on greenhouse gas emissions and contained no enforcement provisions (these would come later in the Kyoto Protocol and, we hope, in a forthcoming climate treaty that will replace it), it did set an ambitious science-based goal: to stabilize greenhouse gases in the atmosphere at a level that will prevent the effects of dangerous climate change.

Scientists say we can only achieve this goal if we radically reduce all major sources of heat-trapping greenhouse gas emissions.

While much of the debate and action has focused on curbing emissions from burning fossil fuels such as oil, coal and gas, the destruction of our forests, wetlands, grasslands and peatlands is responsible for about one quarter of all other emissions into the atmosphere. That’s higher than emissions from cars, trucks, boats and planes together.