Eh, the article is a real stretch. It's about research in an MDPI journal (MDPI is one of the lower-tier publishers), whose actual title is Effects of High Irradiance and Low Water Temperature on Photoinhibition and Repair of Photosystems in Marimo (Aegagropila linnaei) in Lake Akan, Japan. It only discusses climate change very obliquely.

> In the present study, as we used the dissected filamentous cells, the results might be only valid at the cellular level. In fact, we did not consider the effects of the morphological structure of the spherical marimo on the protection of PSII against the exposure to high illumination. Nonetheless, our results provide an indicator or clue to what may happen to the spherical marimo in Lake Akan. The fact of the cell death caused by the photoinhibitory treatment for only 6 h at 2 °C suggests that photoinhibition would be a serious threat to the surface part of marimo in the lake when global warming proceeds. The natural habitat of marimo receives more than 10 h of sunlight, even in winter. > > If the damage of the surface cells increases under the longer exposure to direct sunlight per day due to the thinning of ice or ice collapse, in an extreme case, this may affect maintenance of their round bodies and lead to the disappearance of giant marimo. There is another possibility. It is known that phytoplankton in lake water increases when the lake surface is unfrozen. This suggests a greater absorption of sunlight by the lake water, and it might alleviate photoinhibition in marimo at low temperatures. Nonetheless, the irreversible photoinhibition of PSII in the filamentous cells indicated by this study suggests that this may cause survival of marimo to be more difficult in the near future. If global warming proceeds, there must be a stage where ice will melt away to allow high light penetration to the lake bottom while the water temperature is still low. We need to monitor the environmental conditions in Lake Akan continuously and to examine characteristics of the photoinhibition and repair at low temperatures in the spherical marimo themselves. Furthermore, we must urgently deal with protecting the marimo habitat.

So, as far as this sort of research goes, it's very much preliminary. They have identified a set of environmental conditions which is dangerous to the marimo in the lab, but they do not actually how much warming there needs to be in order for those conditions to occur in the real world (any journal of greater quality than MDPI would have demanded that from them) - or even if they would necessarily occur at all.