Environmental activist Greta Thunberg's recent remarks against world leaders on not doing enough on climate change are also leading to reactions from the United Nations. A senior official from UN Environment today said that he understands and resonates with Ms Thunberg's comments but it is a complicated subject and everybody needs to work harder to change the situation.

Niklas Hagelberg, Coordinator of UN Environment's sub-programme on Climate Change said, "I am also frustrated. By now the science has been clear for years. It has been clear for longer than I have lived on this planet and I am 47 years old. But it's a very complex issue that we are talking about. It is a common atmosphere so every emission goes into the same pot. It comes from everything - from our food systems to how we move around. I understand the "blah blah". I feel like that many times and we need to work harder. From individuals to private sector and governments, everybody needs to pull up their socks."

Mr Hagelberg made the remarks while responding to questions from a group of journalists from around the world, during a virtual address.

He also highlighted that unification towards the issue gets harder as each country comes to the table with its own interests. He said, "There is an Article called Article 8 under the Paris Agreement... Article 8 on "Loss and Damage" and its being negotiated. It is connected to the finance issue. It is currently being discussed but its turning out to be one of the most difficult things and I don't know if countries will be able to agree on it.

Each of these countries when they come for negotiation have a different position, different interests, different circumstances and it is difficult for them to find that common ground. I think that is what largely Greta with her "blah blah blah" comment referred to. That you all keep on talking. But the truth also is that one country maybe sinking, the other's GDP might be heavily dependent on fossil fuels, especially countries in the Middle East and it is an overhaul of their entire economy.

With some countries, 90 per cent of their GDP is dependent on fossil fuels. We as United Nations would never go out and say that a specific country is a problem but yes sharing of common ground is complex in nature."

Greta Thunberg had recently criticised global leaders over their promises to address the climate emergency and dismissed them as "blah, blah, blah" while she was giving a speech at the Youth4Climate summit in Milan on Tuesday.

She quoted statements by UK's Boris Johnson: "This is not some expensive, politically correct, green act of bunny hugging," and Prime Minister Narendra Modi: "Fighting climate change calls for innovation, cooperation and willpower".

Ms Thunberg then said, "Build back better. Blah, blah, blah. Green economy. Blah blah blah. Net zero by 2050. Blah, blah, blah". "This is all we hear from our so-called leaders. Words that sound great but so far have not led to action. Our hopes and ambitions drown in their empty promises. Of course we need constructive dialogue. But they've now had 30 years of blah, blah, blah and where has that led us? We can still turn this around - it is entirely possible. It will take immediate, drastic annual emission reductions. But not if things go on like today. Our leaders' intentional lack of action is a betrayal toward all present and future generations."