Exactly a year ago, on Sept. 20, 2017, one of the most violent storms ever to hit the Caribbean made landfall on the island of Puerto Rico. The storm, the likes of which Puerto Ricans had not seen in several generations, had gathered in intensity before tearing through Dominica and the U.S. Virgin Islands, and ending in Puerto Rico.

No one can deny the devastation that Hurricane Maria brought on the population of Puerto Rico. Most people survived the hell of the storm but were then forced to live through the hell of the aftermath. Food and water shortages were pervasive throughout the island, power was virtually wiped out, hospitals were closed because of extensive damage, and basic services all but collapsed.

No one can deny either that under these dire circumstances, with vital access to healthcare severely disrupted, the death toll would inevitably rise. Yet that is precisely what President Donald Trump did. He has consistently refused to look beyond the initial death toll from the storm, and flatly denied the deaths of nearly 3,000 people in the six months following the storm. This is a bare-faced lie, and one that is inflicting more pain on Puerto Ricans as they mourn.

But the story of how Hurricane Maria was able to have such a devastating impact started well before the storm system began its dizzying rotation over the moist air of the Atlantic.

Hurricane Maria has bought to the surface underlying human rights concerns that have been present for decades. Despite being part of one of the richest countries in the world, nearly half of Puerto Ricans live in poverty, compared to the national U.S. average of 12.7%. The U.S. territory faces a serious financial crisis as a result of crippling external debt of more than $70 billion. Far-reaching austerity measures designed to address this crisis have cut deep into essential public services like healthcare, leaving already vulnerable communities even more exposed.

While the response to the disaster was the largest and longest in the Federal Emergency Management Agency’s (FEMA) history, it has also acknowledged the deficiencies in its own response. A recent report from the U.S. federal government cited Puerto Rico’s “outdated local infrastructure” as a key challenge for FEMA’s operations; it had failed to take into account the island’s 50-year old infrastructure when developing emergency plans. When Maria took out the power grid, communications and transportation infrastructure, it severely impacted FEMA’s response, and left many people at risk of losing access to healthcare and other basic services.

Trump, the person ultimately responsible for the welfare of Puerto Ricans, has wrongly tried to shift the blame solely on to the Puerto Rican authorities for the mounting crisis they face. But it is clear that they too have a lot to answer for.

Puerto Ricans have done everything in their power to protest austerity measures, to try and compel their lawmakers to tackle the expected impacts of climate change on the island, and to build basic disaster preparedness infrastructure that could give them a chance of being safe from future storms.

At best, their protests have fallen on deaf ears. At worst, they have been met with violence: Amnesty International has documented how Puerto Rican authorities responded brutally to these demonstrators, using unnecessary or excessive force.

Now, with far too many people on the island relying on only blue tarpaulin on the roofs of their homes as cover, hurricane season is approaching again. We know that as our planet becomes warmer due to climate change, longer term trend predictions point to a worsening of the intensity of Atlantic storms like Hurricane Maria and Hurricane Florence.

Now, it’s a question of when, not if, another disastrous storm will strike the island.

Faced with this reality, President Trump could choose to act on the information presented to his government by experts—information that gives clear advice on what can be done to try to protect people from the worst effects of such storms. This should urgently include shifting to renewable energy sources, in order to prevent these hurricanes becoming more violent.

Instead, the American people are left with a leader who has tried to deny the very existence of climate change and its existential threat to humanity, to deny that his response to their time of crisis was anything other than an “unsung success,” and to even deny that deaths in their community had occurred.

A year on from the storm, President Trump’s contempt for the wellbeing of Puerto Ricans and the inadequate response of the Federal and Puerto Rican authorities offers us the most frightening lesson of all from Hurricane Maria. Now we know there is something more dangerous to humanity than climate change—that is, a world leader who does not believe it worth trying to protect us from it.

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