Mr Guterres told BBC Scotland it was possible to keep the target alive, but said he is very worried that political divisions could prevent progress.
World leaders have gathered in Glasgow for the annual UN climate conference.
But Mr Guterres said there was a "serious problem of trust" between developed and developing countries.
He urged wealthy countries to make good their commitments to provide $100bn per year in funding for climate change mitigation and adaption in the developing world.
The main aim of the Glasgow talks is to try to hit the target set in the Paris Agreement in 2015, of limiting global temperature rises to 1.5C compared to pre-industrial times.
Some 200 countries are being asked for their plans to cut emissions by 2030, but Mr Guterres told BBC Scotland that a lack of trust between nations was the "most serious problem" the negotiations face.
He said: "I still think it is possible to take decisions to keep 1.5 alive, but I am very worried with the geopolitical divides, with the issues of cooperation namely between developed countries and emerging economies. There is still a long way to go to come to a reasonable compromise.
"I hope that in Glasgow we can solve several serious problems, for instance over the establishment of carbon markets. But the central question is to come to a set of national contributions which guarantees 1.5, it will be very difficult to reach it in Glasgow, which means the next day we must start again.
"I don't think we can wait five years for the next set set of national contributions - from now on it must be a permanent exercise, we must have every year a commitment to improve."
The UN Secretary General said he did not think the potential for a new coal mine in Cumbria or new oil and gas developments elsewhere in the UK "undermine entirely" the UK's leadership on climate change.
He said that while it was not for him to decide the future of the proposed Cambo oil field to the west of Shetland, "we don't need more oil and gas".
On Monday, he told delegates at the conference that "addiction to fossil fuels is pushing humanity to the brink", saying: "We face a stark choice - either we stop it, or it stops us. We are digging our own graves."
Mr Guterres also expressed "enormous gratitude" to Glasgow and the Scottish people for "wonderful hospitality".
The COP26 global climate summit in Glasgow in November is seen as crucial if climate change is to be brought under control. Almost 200 countries are being asked for their plans to cut emissions, and it could lead to major changes to our everyday lives.