Aden has witnessed severe ground fighting since April 2015, and its residents were cut off from fuel, food and medical supplies for months. As a result, some of Oxfam's operations were suspended there, but we continued to work with local water authorities to ensure clean water was pumped to nearly a million people in and around Aden. (Photo: Mohammed Taleb / Oxfam)

The conflict in Yemen, which the US has fueled by supporting the Saudi-led coalition, has killed and injured thousands and brought the entire country into crisis. President Obama’s visit to Saudi Arabia this week is an opportunity to help bring about a sustainable peace.

Scott Paul is a senior humanitarian policy advisor at Oxfam America. 

You’re a good humanitarian and a global citizen. You’ve read up about the crisis in Syria and called on President Obama and Secretary Kerry to help end the crisis.  You opened your wallet for the victims of the earthquakes in Haiti and Nepal. Your heart breaks when you think of refugees being denied entry to Europe. You’ve done your homework and you’re empowered to take action.

And yet, odds are you probably don’t know much about Yemen, where the US has fueled a war over the past year that has created one of the world’s biggest humanitarian crises.

This week, President Obama will visit Saudi Arabia, Yemen’s neighbor to the North and a party in the war that has consumed the country. The conflict will definitely be a point of discussion for the President’s visit. Here’s what you absolutely have to know.

1. More people need humanitarian assistance in Yemen than anywhere else on the planet. 21.2 million people, to be precise. For those of you doing back-of-the-envelope math, in a country of over 25 million people, that’s more than four out of every five Yemenis.
2. More than 6,100 people have been killed and more than 19,520 have been injured. Most of those have been civilians, and two thirds of the deaths have been caused by US-supported coalition airstrikes.
3. Yemen is one of the world’s most water scarce countries. Its capital Sana’a has been projected to become the first in the world to run dry – and that was before the conflict began.
4. Yemen is nearly entirely dependent on imports for food, fuel, and medicine. Yemen produced some fuel before the war, but its refineries have been heavily damaged.
5. The coalition’s de facto blockade has been absolutely devastating. For the better part of a year, the Saudi-led coalition has imposed a “licensing and inspection regime” that has partially, and at times completely, blocked commercial and humanitarian shipments. At times, Yemen has received less than five percent of its food and fuel needs.
6. Banking problems are making the situation worse. As the Central Bank of Yemen runs out of foreign money, its ability to support imports has declined. It’s incredibly difficult to get cash into or out of the country, which has also had an effect on remittances from the diaspora. The net effect of all this is to push food prices even further out of the reach of Yemenis.
7. The risk of famine is real and imminent. Thanks to the conflict, the de facto blockade, the banking challenges, and other issues, approximately half of Yemen is one step away from famine, according to the UN food agency.
8. Yemen’s health care system has collapsed. Since airstrikes began in March 2015, over 600 health facilities have closed due to damage, lack of supplies (including electricity), or absence of staff. As a result, over half the country is without access to basic health services.
9. Children are paying a huge price. According to a report from the UN Children’s Fund, more than 900 children have been killed due to conflict, and mostly due to coalition airstrikes. 10,000 children under five years of age have died of preventable diseases, due to the collapse of the Yemeni health care system.
10. The US has played a role in creating this crisis – and can help end it. All sides of the conflict are responsible for causing this massive humanitarian crisis. The US, which has supported the Saudi-led coalition responsible for causing two of the casualties through the use of airstrikes and explosives in civilian areas, does not have clean hands. While the US has sought to bring an end to the crisis and improve the humanitarian situation, it has continued to support the coalition – including through major arms sales – because it’s unwilling to jeopardize its close relationship with Saudi Arabia and other Gulf states to do it. As a result, Saudi Arabia has actually cited US support to deflect criticism of its conduct in Yemen.

President Obama’s trip to Riyadh comes at a critical stage. With a recently agreed ceasefire gradually – and unevenly – taking hold across the country, and peace talks just beginning, President Obama could apply the pressure needed to push the coalition and the Government of Yemen to prioritize peace over their own interests. However, President Obama needs to arrive in Riyadh prepared to demonstrate that the US is willing to extricate itself from the coalition if the ceasefire and talks fail. Peace talks have already been postponed as of this writing, with the parties accusing each other of intransigence and bad faith. If negotiations fall apart and President Obama poses for a photo op without a meaningful course correction, he could embolden the coalition and enable another year of this devastating war. That would be a profound injustice for the millions of Yemenis whose lives hang in the balance.