Civilians trapped by intense fighting, crippling starvation, threats of abuse and murder … these are just some of the concerns for the United Nations when it comes to humanitarian crises around the world.

Al Jazeera sat down on Thursday with Stephen O’Brien, the UN humanitarian affairs chief, to discuss these challenges, including an impending humanitarian catastrophe in Iraq, the ongoing refugee crisis across Europe and the international community’s obligations when it comes to tackling global problems.

Al Jazeera: In Iraq, there are warnings about a humanitarian catastrophe as the battle for Mosul gathers pace and huge numbers of civilians could flee those areas. How well prepared is the UN to deal with this, and what needs to be done?

Stephen O’Brien: We have known this [the battle for Mosul] is likely to come for some time. Yes, we have had a chance to prepare. We’ve been out raising money – we’ve managed to raise about 50 percent of what we calculated we needed. We certainly need more now, because cash immediately buys you the shelters and the preparation of emergency sites to receive people as they flee.

READ MORE: As Mosul push unfolds, civilians face ‘impossible choice’

At this stage, we have about 60,000 [tents] prepared, 250,000 sites getting ready, but we calculate that there could be between one to 1.5 million people who could flee. But we don’t know. All such military actions do produce very chaotic and unpredictable results. We don’t even know in what direction they may flee.

What we know is we need to be as prepared as we can, and as nimble and as quick as we can, in order to make sure we save lives. The biggest concern we have is the protection of civilians in this conflict so that as the forces advance to seek to take back Mosul, and it does look like a very tough combat – house-to-house, very vicious – that every effort should be made to make sure that innocent civilians can be protected in order for them to survive.

More than 4,200 lives have been lost in the Mediterranean Sea this year [EPA]

Al Jazeera: Moving on to the refugee crisis, as more and more people continue dying trying to make the journey to Europe, should Western governments be doing more to help them? Or are they, as some people believe, a threat to Europe?

O’Brien: What’s clear is that there are huge numbers of people that are feeling compelled to move, who want to get away from either conflict, or they want to get away from deep poverty or chronic diseases – whether that’s from the Sahel in Africa, or Afghanistan, where violence is flaring up again, or wherever they are coming from.

I think the first condemnation should be for the absolutely abhorrent traffickers, who peddle these very dangerous journeys at great cost and don’t care about the fate of the people they send into the open sea.

I think [what] is important, as indeed the United Nations did at a very important worldwide meeting on September 19, is how do we find a better way for us all to step up to our mutual obligations, to receive people in need, to process asylum seekers quickly, to make sure they’re entitled to the life support and the humanitarian goods and services that we would all expect if we were suddenly thrust into a crisis ourselves. That’s the very least we should expect.

So yes, there’s a big debate going on about the respective obligations around the world for these issues, but we should be tackling the root causes, which is what are driving people: conflict and poverty is the source of it.

Al Jazeera: But addressing the root causes costs money. What do you say to those governments in the West, particularly in Europe, who don’t believe that money for international aid and international development is a priority?

O’Brien: I say it’s in everybody’s interest. We absolutely have to be part of what is a globalised world now. We don’t just mean globalised in terms of goods and services for the private sector, we mean globalisation in terms of information flow.

About 135 million people around the world tonight will need some form of humanitarian assistance, and 80 percent comes out of conflict.

We have to be absolutely clear that it’s in our mutual interest to actually dedicate part of those countries which have tax revenues to support private charitable donations and other private sector [initiatives], and even civil-military cooperation from time to time – particularly in natural disasters – to bring every effort to bear in order to meet the humanitarian needs of people wherever they arise … impartially, neutrally and independently.

That is what will help create a more secure world for all of us, so it’s in our mutual interest. And that’s why I think that there is a real need to continue very strongly to prosecute the case that international aid, whether it is humanitarian or development, is something that is of domestic interest as much as it is of international.

Residents inspect a damaged site after an air strike in a besieged rebel-held neighbourhood of Aleppo in Syria [Abdalrhman Ismail/Reuters]

Al Jazeera: Let’s talk solutions and the lack of them at this point, particularly at the UN security council. Many people are frustrated at the sort of gridlock that’s going on there and the perception that it’s become so politicised right now. Is that a frustration that you and your staff feel?

O’Brien: I think everybody is frustrated that we can’t find our way forward … that is likely therefore to yield the result that we want, which is to find a political settlement that is going to last and give the people of Syria the chance to have the kind of life that you and I would expect – which is to be allowed to thrive and to be able to have that sense of security which we all expect to live in.

So yes, there is shared frustration everywhere, but the question arises … There’s no alternative. However much we’re knocked back, however much we’re deterred, and particularly as humanitarians with emergency relief and needing to get that through safe, unimpeded, wherever it is, we need to … call out the facts.

When we say what the facts are on the ground to try and appeal to the consciences of all those involved in these discussions to find a way forward, to find agreement. And even where it’s not found, to try and try again because it is the only option we’ve got.

There isn’t a higher diplomatic body of the world. We have to try and make the security council work.