"This is one of the most important meetings in the history of the IPCC," said Intergovernmental Panel on Climate Change President Hoesung Lee.

Climate change is already wreaking havoc across our planet and the world’s climate scientists just warned us that it can get much, much worse.

From the dramatic rains of hurricanes (Florence, Harvey, and Irma all hit within 12 months), to the extreme droughts in East Africa, we are witnessing the shocking examples of our new climate reality in real time. Rising global temperatures means erratic weather patterns—droughts, heat waves, hurricanes and flooding—will only become more frequent and more devastating. The blows are more ferocious; and the vulnerable people in harm’s way are feeling the impact most acutely.

More than a century of unsustainable growth has resulted in a one degree Celsius (2.7 degrees Fahrenheit) increase in global temperatures above preindustrial levels. According to the Intergovernmental Panel on Climate Change (IPCC)’s newly released report, we are witnessing the beginnings of massive displacement and a rise in hunger. The IPCC has already found evidence of farmers migrating as temperatures increase, which exacerbates inequality as those least able to cope are increasingly forced to uproot their lives.

Although limiting global warming to 1.5 degrees Celsius is an aim of the Paris Agreement, the report makes clear that there is no safe level for climate change. Even a 1.5 degree increase could push tens of millions of people into poverty. Climate change is becoming a poverty multiplier.

But the difference between 1.5 degrees and 2 degrees is also stark, which is why the goals of the Paris Agreement are so important. If temperatures go up to 2 degrees, that makes 62-467 million people more vulnerable to climate impacts and poverty. Ice regularly disappears in the North Pole as rising seas swallow up the homes of at least ten million more along the coasts.

Currently, the collective commitments made by countries as part of the Paris Agreement (which President Trump has indicated the US will leave, but the rest of the world supports), puts our planet on an approximately 3 degree trajectory if everyone meets their commitments. A sobering example of why Trump’s “America First” agenda is a false choice.

While climate change has already been set in motion, we can still act swiftly to reduce emissions and work with communities to adapt to known climate threats. Doing so now means we face fewer tradeoffs and millions of lives can be saved.

However, the IPCC’s analysis makes clear that not all pathways are created equal: there are ways to get to 1.5 degrees that are just and could help lift people out of poverty, and there are ways that force impossible tradeoffs, like choosing between farming land for food and farming land for carbon sequestration. We have to pursue the former. For example, getting coal out of the global energy mix by 2050 is not only possible but necessary, according to the IPCC, and it provides the added bonus of reducing soot that is also compromising health and economic development. Aggressively going after reductions in super pollutants such as methane from natural gas production leaks, can similarly provide pro-poor mitigation solutions that also benefit human health and crop yields.

While the Trump administration continues to ignore the warnings of climate scientists and be laser-focused on undoing policies that could help move the US toward a cleaner and more equitable economy, cities, states and businesses across the country are stepping in and taking their own actions.

Around the world, the clean energy revolution continues unabated, with the dropping price of renewable energy increasingly making it the better option. Renewable energy also continues to be the best solution for the millions of people presently lacking access to safe and affordable electricity, offering real win-win outcomes for the world’s poor.

Some of the poorest and lowest emitting countries are also taking action, leading the fight against climate change despite being the least responsible for creating climate change. More such acts of bold ambition are needed, particularly from the wealthiest and most resilient among us, if we are to change course and leave a habitable planet to our children and the generations to come.