In the year 1992 Union of Concerned Scientist organized petition called ‘World Scientists‘ Warning to Humanity’. The world is becoming worse. In the October of 2017 Bioscience journal published sequel with appendix ‘Second Notice’. It was signed by 15 000 people from various scientific fields and students.
A lot of news referred to it(for example Forbes or CBS).
The petition ends with exclamation: ‘Soon it will be too late to shift course away from our failing trajectory, and time is running out.’ Which was the most common part cited by media.
In contrary of other petition signed by about 30 000 scientist, which states ‘There is no convincing evidence that human release of carbon dioxide, methane, or other greenhouse gases is causing or will, in foreseeable future, cause catastrophic heating of the Earth’s atmosphere and disruption of Earth’s climate.’
That’s just to convince you, that the number of scientist doesn’t say anything about the argument itself.
The first point of my criticism is that the petition warns about vertebrate species extinction. Their numbers show that current vertebrate population has shrunk to 42% of the vertebrate population in the 1970. I personally find that a bit overstated.
The number of monitored populations which decline is roughly equal to those which increase their numbers. When it’s so balanced small error can result in massive distortion.[4,5]
Methodology of those calculation was also criticized by ecologist like Duke Primm ‘The new living planet index is seriously flawed — mixing as it does, good numbers and “very, very sketchy ones”’.
The next point of my criticism is complaining about deforestation at Amazon or Borneo. There’s no doubt that this deforestation is happening and is bad, but recent articles suggest that it is compensated by the gain in other regions and global terrestrial biomass is rising.
The final point of my criticism is threatening with overpopulation, which is not common in scientific literature. It was described, that current population boom is effect of so called demographic transition – growth of standard of living, causes population boom to slow down. For example in Turkey and Iran the fertility rate is now just 2.0 births per woman – which is just the right number to sustain a population. In India it’s 2.5 and in Morocco it’s 2.3. 
Graph2: Demographical transition. People used to have a lot of children because of the high mortality. Then when the mortality had dropped, population boom had began. Then people got used to higher living standard and the natality also dropped.
 Living Planet Report 2014 , Figure 8, Page 18, https://www.wwf.or.jp/activities/data/WWF_LPR_2014.pdf
 World wildlife ‘falls by 58% in 40 years’, BBC News, 27.10.2016, http://www.bbc.com/news/science-environment-37775622
 Vegter, I. WWF alarmism raises even green eyebrows, Daily Maverick, 6.10.2014, https://www.dailymaverick.co.za/opinionista/2014-10-06-wwf-alarmism-raises-even-green-eyebrows/
 Liu et al. Recent reversal in loss of global terrestrial biomass, Nature Climate Change, 30th March 2015).
Roudi-Fahimi et al. Demographic trends in muslim countries. Population Reference Bureau. http://www.prb.org/Publications/Articles/2013/demographics-muslims.aspx