Researchers have found a 21% decline since 1961. It is not a hard decline it is a relative one.
In 1961 the global population was 3 billion compared to 7.6 billion today - a 2.5 times increase. If we were producing 1 million tons of something back then we would need to be producing 2.5 million tons today, but we are not, we are down to 2 million tons.
This declines is despite all the deforestation and use of fertilizers. The deforestation has largely been done to mitigate the damage done to the soil and create farming land. In some areas we have created what are almost deserts on previously productive arable land.
Throw in the damage done to crops due to climate change and you have the perfect storm. Cut down the trees, which take up some of the CO2, in order to grow more food yet damage the soild and the atmosphere in the process. It is hurting the seas and fish stocks as well.
God only knows what the answer is. We are in a pandemic at the moment and all we can think about is getting back to normal. You know, thet "normal" where we trashed the planet at an ever increasing rate!