Listen and read 43: Climate Change - Thấm Tâm Vy

Nội dung text: Listen and read 43: Climate Change - Thấm Tâm Vy

1. LISTEN AND READ 43 Running these simulations over and over again in order to get statistically reliable results suggests that cutting CO2 emissions could slow the rate of Climate Change warming as early as 2033, but only if they are ended worldwide in 2020. In Delayed Cool effect, that would mean eliminating 80% of the world’s energy sources, including shutting down all fossil-fuel power stations, overnight—clearly not a Emissions slashed today will be felt only in the middle of the century realistic or desirable scenario. Reducing CO2 by 5% per year, starting this year, MUCH OF the international effort thus far to would produce a statistically significant deviation combat climate change has focused on cutting from what temperatures would have otherwise been emissions of greenhouse gases, chief among them only in 2044. And yet, even that rate of CO2 carbon dioxide. That is, of course, a rational reduction is ambitious, on a par with the 4-7% drop approach. Global average temperatures are roughly estimated this year as a result of the covid-19 1.1°C warmer today than in pre-industrial times and pandemic and widespread economic shutdowns. CO2 is the main culprit. It and other greenhouse gases Before this, annual emissions were creeping up. are produced when fossil fuels are burned to generate Without concerted efforts from governments, they energy or power engines, in steel and cement- are likely to rise again as economies reopen. making, by farming and deforestation. In the long One reason for the delayed effect of slashing term, eliminating these emissions is the only emissions is natural variability in the climate. sustainable solution for stopping the inexorable Whether one year is warmer or cooler than the warming of the planet. previous is not simply down to greenhouse gases. But greenhouse-gas emissions do not cause an Large-scale natural climate effects also play a role instantaneous rise in global temperatures, and neither (El Niđo and La Niđa are perhaps the best-known does cutting them result in instantaneous cooling. examples), warming and cooling the planet in a Instead, it will take decades for today’s policy efforts cyclical fashion by fractions of a degree. Depending to result in measurable impacts on global on their phase, the warming of greenhouse gases is temperature—as illustrated in a study published this either masked or compounded by these kinds of week in Nature Communications. natural effects. As emissions begin to drop, natural Using climate models, Bjorn Samset and his variability will also mask any slowdown of global colleagues at Norway’s Centre for International warming that results. Dr Samset’s modelling took Climate Research probed hypothetical futures in this into account. which emissions of nine different industrial In addition, more than 90% of the energy trapped by pollutants, including carbon dioxide and methane, the greenhouse-gas emissions produced in the past were either eliminated instantly or phased out at a half-century has been stored in the ocean and rate of 5% each year, starting in 2020. In order to released to the atmosphere as heat only slowly. Even isolate their respective effects, each chemical was if all emissions were cut tomorrow, that process knocked out individually while the rest were allowed to keep evolving as they would continue to warm the air above for many years to come. would broadly if governments stuck to current climate pledges. Thus, the The main reason for the delay, however, is that carbon dioxide emitted today experiment tested how quickly additional efforts, as required by the Paris will remain in the atmosphere for decades to centuries before it is reabsorbed by Agreement, would be seen in the rate of global warming. vegetation and the oceans. That is not true of other industrial emissions. Each molecule of methane warms the planet 84-87 times more, averaged over 20 TTTV LISTEN AND READ 43
2. years, than carbon dioxide, but it stays aloft for merely years instead - Paris Agreement: an agreement within the United Nations Framework Convention of decades or centuries. This has on Climate Change (UNFCCC), dealing with greenhouse-gas-emissions mitigation, resulted in calls for immediate adaptation, and finance, signed in 2016. The agreement's language was negotiated by action to slash methane emissions, representatives of 196 state parties at the 21st Conference of the Parties of the for instance by plugging leaks in UNFCCC in Le Bourget, near Paris, France, and adopted by consensus on 12 December natural-gas infrastructure, and 2015. As of February 2020, all UNFCCC members have signed the agreement, 189 have reducing emissions from farming. become party to it, and the only significant emitters which are not parties are Iran and Turkey. But even then, Dr Samset’s work The Paris Agreement's long-term temperature goal is to keep the increase in global suggests that eliminating all sources average temperature to well below 2 °C above pre-industrial levels; and to pursue of methane pollution in 2020 would efforts to limit the increase to 1.5 °C, recognizing that this would substantially reduce not affect warming trends before the risks and impacts of climate change. This should be done by reducing emissions as 2039. soon as possible, in order to "achieve a balance between anthropogenic emissions by Keep up the pressure sources and removals by sinks of greenhouse gases" in the second half of the 21st Tragically, the pollutant that could century. It also aims to increase the ability of parties to adapt to the adverse impacts of climate change, and make "finance flows consistent with a pathway towards low have the most immediate impact is greenhouse gas emissions and climate-resilient development." one that currently keeps the world cooler. Sulphur oxides are a by-product of Under the Paris Agreement, each country must determine, plan, and regularly report burning some fossil fuels, including coal and dirty bunker fuel, and are a target on the contribution that it undertakes to mitigate global warming. No mechanism forces of policies to clean up maritime emissions and urban air pollution. In the a country to set a specific emissions target by a specific date, but each target should go atmosphere, they bounce a portion of solar radiation back out into space, beyond previously set targets. In June 2017, U.S. President Donald Trump announced producing a cooling effect. Because they are dragged back to Earth by rain his intention to withdraw the United States from the agreement. Under the agreement, within days of being emitted, cutting them out of industrial activities could boost the earliest effective date of withdrawal for the U.S. is November 2020, shortly before the end of President Trump's 2016 term. In practice, changes in United States policy warming by the end of the decade. that are contrary to the Paris Agreement have already been put in place. [Wikimedia] In spite of all this, mitigating emissions remains crucial to the stability of the global climate and the only way of meeting the Paris Agreement targets of limiting global warming to 1.5-2°C. But Dr Samset argues that temperature may not be the best yardstick to measure the effectiveness of climate mitigation, at least not until the 2040s. Instead, direct measurements of the concentrations of greenhouse gases in the atmosphere may be better, as they will remove the confounding effect of natural variability. And without clever messaging, there could be a public backlash against seemingly ineffectual policies. More fundamental, however, results like these underline that even as economies begin to decarbonise, governments and societies need to drastically step up efforts to adapt to the inevitable warming that lies ahead. . [The Economist US 11.07.2020] Notes: - inexorable: khơng lay chuyển được - to probe: thăm dị = examine throroughly - on a par with: ngang tầm (với) - slashing: khai quang - bunker fuel: nhiên liệu cho tàu thủy - backlash: gây phản ứng ngược - drastically: quyết liệt TTTV LISTEN AND READ 43