The pace of new patenting for several categories of climate-friendly technologies has seen a "notable drop-off" since 2012, according to a July 11 analysis from the IEA and OECD.

Why it matters: While far wider deployment of existing tech can do a great deal to stem carbon emissions, the steep cuts needed to meet the Paris Agreement temperature goals will likely require substantial innovation.

What they did: The analysts explored the pace of patenting in several groupings of emissions-cutting tech (see chart above). They noted that several other fields — including health and IT — have not seen this drop-off.

"Some of this decline could be explained by the increasing 'maturity' of climate change mitigation technologies, and thus lower propensity to patent."

But, but, but: It's not all gloom and doom. Some areas have bucked the trend, such as "enabling" tech for integrating storage into power systems, and cleaner shipping.

The bottom line: The core finding is concerning despite some bright spots, the IEA and OECD analysts say, noting for instance that today's competitive costs for wind and solar are the fruit of R&D in past decades.