Warning "life or death": a large study indicates that the world has only 11 years to avoid the catastrophe of climate change | national

Intro

Governments around the world must take "swift, far-reaching and unprecedented change in all aspects of society" to avoid disastrous levels of global warming, says new report grabbing authority global scientist on climate change.

The report released Monday by the UN Intergovernmental Panel on Climate Change (IPCC) indicates that the planet will reach the crucial threshold of 1.5 ° Celsius (2.7 ° F) relative to at preindustrial levels by 2030, which will reduce the risk of extreme drought, forest fires, floods and food shortages for hundreds of millions of people.

The date, which falls well in the lives of many living people today, is based on current levels of greenhouse gas emissions.

The planet is already two-thirds of the way, with warming global temperatures of about 1 degree C. To avoid going even higher, important measures will have to be taken in the coming years.

"This is disturbing because we know that there are many more problems if we exceed global warming by more than 1.5 ° C, with more heat waves and hot summers, a larger rise in sea ​​level and, in many parts of the world, droughts and extreme rainfall "Andrew King, a lecturer in climatology at the University of Melbourne, said in a statement.

Global net emissions of carbon dioxide are expected to fall by 45% from 2010 levels by 2030 and reach "net zero" by 2050 to maintain warming around 1.5 ° C.

Reducing emissions at this level, while technically possible, would require widespread changes in the fields of energy, industry, buildings, transport and cities, the report says.

"The window on maintaining global warming at less than 1.5 ° C is closing fast and the current emissions pledges made by the signatories of the Paris Agreement do not allow us to go into the future. achieve that goal, "added King.

"For some people, it is undoubtedly a life-and-death situation," said Natalie Mahowald, a scientist in climatology at Cornell University, lead author of the report.

Consequences of past inaction

The report makes it clear that climate change is already happening – and that the next step could be even worse, unless urgent international policy measures are taken.

"One of the key messages that emerges very clearly from this report is that we are already seeing the consequences of global warming of 1 degree C by more extreme weather, rising sea levels and a decrease in Arctic sea ice, among other changes, "said Panmao. Zhai, co-chair of IPCC Working Group I

Even if the warming is maintained at or just below 1.5 ° C, the impacts will be widespread and significant.

The report states that temperatures during summer heatwaves, such as those just experienced in Europe this summer, are expected to increase by 3 ° C.

More frequent or more intense droughts, such as the one that almost shut off taps in Cape Town, South Africa, as well as more frequent extreme precipitation events, such as hurricanes Harvey and Florence in the United States, are also expectations. reach the threshold of warming.

Coral reefs will also be hit hard, between 70 and 90% of them being about to die, including the Great Barrier Reef, in Australia.

Countries in the southern hemisphere will be among the most disadvantaged, according to the report, "who should suffer the greatest impacts on economic growth because of climate change if global warming intensified".

The report points out that even the slightest increase in the basic objective would worsen the impact of recent natural disasters.

"Every little extra warming is important, especially since a warming of 1.5 ° C or more increases the risk associated with lasting or irreversible changes, such as the loss of certain ecosystems," said Hans-Otto Pörtner , co-chair of the IPCC working group. Group II.

The report cites specific examples of how the effects of global warming would be mitigated with the increase of 1.5 ° C compared to the 2 ° C increase:

• The sea level would increase by 10 cm by 2100.

• The probability that an Arctic Ocean would be free of sea ice in the summer would be once in a century, at least once a decade.

• Coral reefs would decrease from 70% to 90% instead of being almost completely annihilated.

"Possible with the laws of chemistry and physics"

Monday 's report has been under development for three years and is a direct result of the Paris agreement on the 2015 climate. In the Paris agreement, 197 countries have started to work in the country. agreement on the goal of keeping global temperatures "well below" 2 degrees Celsius from pre-industrial levels and to continue their efforts to limit them to 1.5 degrees C.

The United States was initially in agreement, but President Donald Trump pulled the country out a year and a half later, saying it was unfair to the country.

Limiting global warming to 1.5 degrees C is "possible in the laws of chemistry and physics," said Jim Skea, co-chair of IPCC Working Group III. "But that would require unprecedented changes."

"International cooperation is absolutely essential to limit emissions and therefore global warming and its impacts, as well as to coordinate effective and widespread adaptation and mitigation," said Sarah Perkins-Kirkpatrick, a researcher at Climate Change Research Center. 39, University of New South Wales. . "The next few years will be decisive for the evolution of these efforts."

Negative emissions, large – scale carbon – cleaning technologies capable of reducing the amount in the atmosphere and combating continuous pollution will be a key problem.

According to the report, there are two main methods for removing carbon from the atmosphere: the growing natural processes that already do it and the experimental technologies for storing or removing carbon.

However, all methods "are at different stages of development and some are more conceptual than others because they have not been tested on a large scale," the report warned.

They will also require significant global political commitment, as well as reducing the amount of carbon emitted. Despite the report's warnings, there is no indication that such cooperation will be feasible, especially given the Trump administration's position on this issue.

"Today, the world's leading scientific experts have collectively reinforced what Mother Nature has made clear, namely that we must undergo an urgent and rapid transformation into a global clean energy economy," she said. former US Vice President Al Gore.

"Unfortunately, the Trump administration has become a sneaky figure in its short-sighted attempt to support the dirty fossil fuel industries of the past. The administration is in direct conflict with the companies, states, cities and US citizens who are leading the transformation. "

Here's what consumers can do

IPCC models emphasize the need for people to change their lifestyles and patterns of consumption to adopt more sustainable alternatives, particularly in areas they can control, such as modes of transport, buildings they live and their food preferences.

"This is a new way for the IPCC to report on mitigation pathways – carbon budgets are so tight at 1.5 ° C that we need to take aggressive action at the political, business and industry, but also from consumers ", Chris Weber, Climate Specialist at Wildlife Fund, told CNN.

When asked if consumers could help achieve this goal, Weber replied, "unequivocally, yes."

Transport: To reach the goal of 1.5 ° C, the IPCC envisions a future in which people travel less and that consumer preferences generally shift to more sustainable choices, such as car-sharing and hybrid cars and electric. The report also examines the use of more efficient modes of travel, for example. exchange cars, trucks and planes for buses and trains.

buildings: Although this section is less prescriptive, the IPCC suggests that people adopt more sustainable behavior with respect to their homes, for example by using smart thermostats or more efficient air conditioners.

Plans: Again, the models are not exhaustive, but in general, the IPCC story suggests that people consume about 30% less animal products. Eating less meat is one of many mitigation strategies suggested by the IPCC to reform agricultural and land use practices, including forest protection. It is estimated that the livestock sector accounts for 14.5% of global greenhouse gas emissions, more than the direct emissions of the transport sector.

These "Shared Socio-Economic Pathways" (SSPs), which focus on mitigation and adaptation to climate change, constitute a relatively new innovation and give a new dimension to climate modeling: the impact changes in human behavior.

"It's very clear just by looking at the archetypal pathways that they've [IPCC] "The consumer's dimensions help reduce emissions much more quickly," said Weber.

Associated Press contributed to this report.