Scott Morrison has taken another, albeit very small, step towards endorsing a target of net zero emissions by 2050.

He told the National Press Club on Monday: “Our goal is to reach net zero emissions as soon as possible, and preferably by 2050”.

This follows his previous wording of wanting net zero “as quickly as possible”.

It remains unclear whether the baby steps will lead to his embracing the 2050 target later this year. But he’d almost certainly like to do so – it would undoubtedly smooth the way with the Biden administration as well as putting Australia in a better position for the Glasgow climate conference in November.

But there are pesky Nationals (and a few others) ready to make the road rocky.

The next climate test for Morrison is President Biden’s planned leaders’ climate summit on Earth Day, April 22.

Climate is at the centre of the Biden agenda, which makes the April summit particularly important.

The President’s climate envoy John Kerry told a White House press briefing last week: “the convening of … this summit is essential to ensuring that 2021 is going to be the year that really makes up for the lost time of the last four years and that the U.N. Climate Conference — COP26, as it’s called, which the UK is hosting in November — to make sure that it is an unqualified success”.

Kerry spoke to energy minister Angus Taylor last week when, according to the Australia readout of the discussion, Kerry “welcomed Australia’s commitment to achieving net zero emissions as soon as possible”.

As, perhaps, one might welcome an infant’s early progress.

Asked on Monday whether he expected to attend the Biden climate conference, Morrison replied cautiously, on the basis of lack of information.

Perhaps he didn’t want to take any risks. In December he was embarrassed when an expected invitation to a speaking spot at the “climate ambition summit” hosted by Britain, France and the United Nations didn’t eventuate. Australia was judged as not having sufficient “ambition” to warrant a slot.

“ At this stage, we haven’t received the details or nature of the event,” Morrison said of the April gathering.

“As you can appreciate, things are very busy over in the White House at the moment.”

When details were received, “then I’m sure the Minister for Foreign Affairs, Marise Payne and I, and Angus Taylor, and others, will discuss what is the best way for us to participate in that and how that will work.

"But we welcome it and we look forward to supporting it.”

Maybe there’ll be more to know when Morrison speaks to Biden. As of Monday, the PM was still waiting fot his first post-inauguration call from the President (they spoke after the election). The Prime Minister’s Office could only say the call was expected “within coming days”.

Morrison on Monday repeated strongly his mantra of advancing climate policy by “technology” not “tax”.

If he does move to the 2050 target, the rationale he will give for the shift will be the progress of technology.

“My commitment to Australians that I will not tax our way to net zero by 2050 is a very, very important one and I will hold my faith with the Australian people on those issues. So we will see how the technology develops,” he said.

If he wished, he obviously could use “technology” at any point as his cover for changing his position. The issue will be if and when he thinks he has the political cover.