Has this rise been caused by humans somehow? And does it pose some sort of threat to life on Earth?
Nature doesn't care about the answers to those questions, she's just grateful there's more CO2 today, and is looking forward to even more by 2060.
Since we now have artificial intelligence that can think much faster than natural intelligence, why can't we have artificial trees that mine CO2 from the sky much faster than natural trees, and put it to use similarly to how trees make energy, namely in their case with ATP from photosynthesis, and lumber, namely in their case by polymerizing glucose?
Regardless of the answers to the above two questions, our approach could be pitched to both sides of the CO2 debate as simply waste management, regardless of who or what is responsible for that newly arrived CO2.
In September I applied for a patent on a design for a synthetic tree, floating in the ITCZ (the "doldrums") and powered by OTEC. The tree combines carbon from CO2 with hydrogen from water vapor along with various trace minerals to form plastic as polymers of various hydrocarbons. It uses the plastic to clone itself three times in its lifetime, creating a forest of descendants according to the tribonacci numbers, aka Darwin's elephants.
In eight generations, a small forest of small trees can grow to a forest of much larger trees having 81 times as many trees as in the starting forest. If a tree can clone itself in six months and be recycled after 18 months, eight generations would take four years.
Any surplus plastic can be shipped to shore and sold to the plastics industry while any surplus energy can be used to power AI datacenters on ships beside trees, cooled by ocean water and connected to the Internet via either satellite or a mesh network supported by the forest.
The USPTO seems to have liked that idea since it allowed all 22 claims of the patent in January, less than four months after applying.
The part of the ITCZ best suited to such a forest is the six million square kilometers on the equator to the north-east of New Guinea, an area 50° x 10° = 500 °². Now 1° = 1000/9 km, so 500 x 1,000,000/81 = 6,172,480 km², amounting to a very large solar panel, with the OML as a thermal "battery backup". Being relatively nearby, both Australia and Indonesia should find the idea interesting.
I envisage a small team spending 2026-2029 researching the details and developing a small forest of small trees, and then growing the large forest largely autonomously during 2030-2035. By then, the forest will be powered by 20 sverdrups of each of warm surface water and deep cold water.
This water rate is about 25 million times the 12,000 GPM of water consumption of Makai Ocean Engineering's OTEC plant, currently the world's largest such at 105 kW. Assuming similar efficiency, the forest would be generating 2.6 terawatts (TW), about 15% of civilization's total 17 TW from all energy sources. At that point, during each second, the forest will be processing 6⁸ tons of air yielding 250 tons of carbon.
Once that rate is achieved, the rate of growth of the forest should slow to mere population replacement to avoid triggering an ice age. The main cost should be for the four years of R&D, along with whatever ongoing support might be needed for otherwise autonomous growth..