[E304]Southwest's Conifers Face Trial by Climate Change

Southwest's Conifers Face Trial by Climate Change

Using climate models[气候模型] and tree physiological data[生理数据], researchers forecast a near-complete annihilation[ənaɪɪ'leɪʃ(ə)n][灭绝；消灭] of evergreens[常青树] in the southwest by the year 2100.

利用气候模型以及树木的胜利数据，研究者预测到2100年常青树将近乎灭绝。

As you sit round the Christmas tree[圣诞树], consider the TLC[abbr. 温柔的体贴tender loving care] you give O Tannenbaum[圣诞歌]: plenty of water and a relatively comfortable climate. Wouldn't want to dry out the tree, after all. Now consider that in the house we all live in—the planet—we’re hardly giving the same courtesy['kɝtəsi][礼貌；好意；恩惠] to your Christmas tree's wild cousins[野生近亲]. (Who, I might add, are actually still alive.)

As the planet warms, droughts[draʊt][干旱] are getting even drier—and they're getting hotter too. In fact it's getting so bad that researchers are now forecasting that conifers['kɑnəfɚ][针叶树;松柏科植物] in the arid['ærɪd][干旱的;不毛的] southwestern United States could be completely wiped out[灭绝;消灭] by the end of the century. No more pinyon pines[松树;沼泽松;四针松], ponderosas[,pɔndə'rəusə][北美黄松；美国黄松木] or junipers['dʒuːnɪpə][杜松；桧或刺柏属植物]. No more forests.

"It's definitely a distressing[悲伤的；使烦恼的] result for all of us. None of us want to see this happen. It's a bummer[坏消息], honestly." Sara Rauscher, a climate scientist[气候学家] and geographer[dʒɪ'ɒɡrəfə][地理学者] at the University of Delaware. She and her colleagues gathered data on how real-world evergreens[常青树] in the southwest respond to drought and heat—they basically starve[饿死；挨饿], unable to carry on photosynthesis[,fəʊtə(ʊ)'sɪnθɪsɪs][光合作用] or transport water.

The researchers then combined those physiological data[生理数据] with a half dozen projections[prə'dʒɛkʃən][预测，推测] of how climate change might proceed. "But no matter what model we used, we always saw tree death." Specifically, 72 percent of the trees dead by 2050, and a near-complete annihilation by the year 2100[到2100年几乎完全灭绝]. The results are in the journal Nature Climate Change. [N. G. McDowell et al, Multi-scale predictions of massive conifer mortality due to chronic temperature rise]

But we'll always have Paris, right? "Even if we used a scenario[sə'nærɪo][方案；情节；剧本] similar to what the Paris accords have agreed upon[同意；商定]—so limiting global warming to 2 degrees—we still saw widespread die-off[相继死亡，物种数量非人为锐减，绝种]. It happened later in the century, but it still happened." That said, the study does not account for[对…做出解释；说明……的原因] trees' ability to adapt, or whether new populations could find friendlier climes[klaɪm][气候；地方]. That is, whether conifers['kɑnəfɚ][松柏类，针叶树；球果植物] in the southwest can pull up roots fast enough to beat climate change.

—Christopher Intagliata

From 60-Second Science