旅游业对全球碳减排构成挑战
澳大利亚科学家研究认为,由于高涨的需求和技术效率提升缓慢,过去十年间与全球旅游业相关的碳排放有所增加。这些发现基于2009~2020年间的数据,凸显出需采取有效政策措施的紧迫性,使旅游业与全球气候目标保持一致。相关研究12月11日发表于《自然—通讯》。
旅游业是全球碳排放的一个主要来源。这一行业的快速增长及其碳密集的性质(尤其是与运输方式相关的特点),对全球减排工作构成挑战。理解旅游业碳排放的关键驱动因素,对于制定策略来缓解这一行业的环境影响十分重要。
昆士兰大学的孙雅彦和同事利用2009年至2020年间175个国家的数据,对全球旅游业碳足迹进行了全面分析。他们发现,全球旅游业排放每年增加3.5%(超过全球经济增长率的两倍,即每年1.5%),在betway体育:年达到了52亿吨二氧化碳当量。这相当于全球温室气体总排放的8.8%。这一增长的首要驱动因素是技术效率增长缓慢(每年0.3%)和旅游需求持续高增长(按2009年不变价格计算,每年增长3.8%)。这项研究还显示出人均旅游排放量上的明显差异,20个最高排放的国家碳足迹占全球总排放量的75%。
这些发现强调有必要采取紧迫的行动来减少旅游业排放。技术进步虽然带来了一定的减排,但不足以抵消旅游业的快速增长。这项研究还强调了设计全球减排政策时考虑经济差异的重要性。(来源:betway体育:科学报 冯维维)
相关论文信息:https://doi.org/10.1038/s41467-024-54582-7
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element block and removes
// previous instances of the identical script.
var found = false;
for (var child = 0; child < head.childNodes.length; child++) {
var control = head.childNodes[child];
if (typeof(control.tagName) == "string") {
if (control.tagName.toUpperCase() == "SCRIPT") {
if (script.src.length > 0) {
if (script.src == control.src) {
found = true;
break;
}
} else if (script.innerHTML.length > 0) {
if (script.innerHTML == control.innerHTML) {
found = true;
break;
}
}
}
}
}
if (found) {
head.removeChild(control);
}
var scriptAddedToHead = false;
if (typeof script.readyState != "undefined" && !window.opera) {
script.onreadystatechange = function() {
if (script.readyState != "complete" && script.readyState != "loaded") {
return;
} else {
Anthem_LoadPageScript(result, index + 1);
}
}
} else {
if (isExternalScript) // if it's an external script, only execute the next script when the previous one is loaded.
{
script.onload = function() {
Anthem_LoadPageScript(result, index + 1);
}
}
else // I didn't find a way for script blocks to fire some onload event. So in this case directly call the Anthem_LoadPageScript for the next script.
{
document.getElementsByTagName('head')[0].appendChild(script);
scriptAddedToHead = true;
Anthem_LoadPageScript(result, index + 1);
}
}
// Now we append the new script and move on to the next script.
// Note that this is a recursive function. It stops when the
// index grows larger than the number of scripts.
if (!scriptAddedToHead)
document.getElementsByTagName('head')[0].appendChild(script);
}
} catch (e) {
Anthem_DebugError("Error adding page script to head. " + e.name + ": " + e.message);
}
}
}
function Anthem_EvalClientSideScript(result) {
if (result.script) {
for (var i = 0; i < result.script.length; ++i) {
try {
eval(result.script[i]);
} catch (e) {
alert("Error evaluating client-side script!\n\nScript: " + result.script[i] + "\n\nException: " + e);
}
}
}
}
//Fix for bug #1429412, "Reponse callback returns previous response after file push".
//see http://sourceforge.net/tracker/index.php?func=detail&aid=1429412&group_id=151897&atid=782464
function Anthem_Clear__EVENTTARGET() {
var form = Anthem_GetForm();
Anthem_SetHiddenInputValue(form, "__EVENTTARGET", "");
}
function Anthem_InvokePageMethod(methodName, args, clientCallBack, clientCallBackArg) {
Anthem_Clear__EVENTTARGET(); // fix for bug #1429412
return Anthem_CallBack(null, "Page", null, methodName, args, clientCallBack, clientCallBackArg, true, true);
}
function Anthem_InvokeMasterPageMethod(methodName, args, clientCallBack, clientCallBackArg) {
Anthem_Clear__EVENTTARGET(); // fix for bug #1429412
return Anthem_CallBack(null, "MasterPage", null, methodName, args, clientCallBack, clientCallBackArg, true, true);
}
function Anthem_InvokeControlMethod(id, methodName, args, clientCallBack, clientCallBackArg) {
Anthem_Clear__EVENTTARGET(); // fix for bug #1429412
return Anthem_CallBack(null, "Control", id, methodName, args, clientCallBack, clientCallBackArg, true, true);
}
function Anthem_PreProcessCallBack(
control,
e,
eventTarget,
causesValidation,
validationGroup,
imageUrlDuringCallBack,
textDuringCallBack,
enabledDuringCallBack,
preCallBackFunction,
callBackCancelledFunction,
preProcessOut
) {
var valid = true;
if (causesValidation && typeof(Page_ClientValidate) == "function") {
valid = Page_ClientValidate(validationGroup);
}
if (typeof(WebForm_OnSubmit) == "function") {
valid = WebForm_OnSubmit();
}
if (valid) {
var preCallBackResult = true;
if (typeof(preCallBackFunction) == "function") {
preCallBackResult = preCallBackFunction(control, e);
}
if (typeof(preCallBackResult) == "undefined" || preCallBackResult) {
var inputType = control.getAttribute("type");
inputType = (inputType == null) ? '' : inputType.toUpperCase();
if (inputType == "IMAGE" && e != null) {
var form = Anthem_GetForm();
if (e.offsetX) { // IE
Anthem_SetHiddenInputValue(form, eventTarget + ".x", e.offsetX);
Anthem_SetHiddenInputValue(form, eventTarget + ".y", e.offsetY);
} else { // FireFox + ???
var offset = GetControlLocation(control);
Anthem_SetHiddenInputValue(form, eventTarget + ".x", e.clientX - offset.x + 1 + window.pageXOffset);
Anthem_SetHiddenInputValue(form, eventTarget + ".y", e.clientY - offset.y + 1 + window.pageYOffset);
}
}
if (imageUrlDuringCallBack || textDuringCallBack) {
var nodeName = control.nodeName.toUpperCase();
if (nodeName == "INPUT") {
if (inputType == "CHECKBOX" || inputType == "RADIO" || inputType == "TEXT") {
preProcessOut.OriginalText = GetLabelText(control.id);
SetLabelText(control.id, textDuringCallBack);
} else if (inputType == "IMAGE") {
if (imageUrlDuringCallBack) {
preProcessOut.OriginalText = control.src;
control.src = imageUrlDuringCallBack;
} else {
preProcessOut.ParentElement = control.parentElement ? control.parentElement : control.parentNode;
if (preProcessOut.ParentElement) {
preProcessOut.OriginalText = preProcessOut.ParentElement.innerHTML;
preProcessOut.ParentElement.innerHTML = textDuringCallBack;
}
}
} else if (inputType == "SUBMIT" || inputType == "BUTTON") {
preProcessOut.OriginalText = control.value;
control.value = textDuringCallBack;
}
} else if (nodeName == "SELECT" || nodeName == "SPAN") {
preProcessOut.OriginalText = GetLabelText(control.id);
SetLabelText(control.id, textDuringCallBack);
} else {
preProcessOut.OriginalText = control.innerHTML;
control.innerHTML = textDuringCallBack;
}
}
// Disable the control during callback if required
control.disabled = (typeof(enabledDuringCallBack) == "undefined") ? false : !enabledDuringCallBack;
return true;
} else {
// Callback cancelled
if (typeof(callBackCancelledFunction) == "function") {
callBackCancelledFunction(control, e);
}
return false;
}
} else {
// Validation failed
return false;
}
}
function Anthem_PreProcessCallBackOut() {
// Fields
this.ParentElement = null;
this.OriginalText = '';
}
function Anthem_PostProcessCallBack(
result,
control,
e,
eventTarget,
clientCallBack,
clientCallBackArg,
imageUrlDuringCallBack,
textDuringCallBack,
postCallBackFunction,
preProcessOut
) {
if (typeof(postCallBackFunction) == "function") {
postCallBackFunction(control, e);
}
// Re-enable the control if it was disabled during callback
control.disabled = false;
var inputType = control.getAttribute("type");
inputType = (inputType == null) ? '' : inputType.toUpperCase();
if (inputType == "IMAGE") {
var form = Anthem_GetForm();
Anthem_RemoveHiddenInput(form, eventTarget + ".x");
Anthem_RemoveHiddenInput(form, eventTarget + ".y");
}
if (imageUrlDuringCallBack || textDuringCallBack) {
var nodeName = control.nodeName.toUpperCase();
if (nodeName == "INPUT") {
if (inputType == "CHECKBOX" || inputType == "RADIO" || inputType == "TEXT") {
SetLabelText(control.id, preProcessOut.OriginalText);
} else if (inputType == "IMAGE") {
if (imageUrlDuringCallBack) {
control.src = preProcessOut.OriginalText;
} else {
preProcessOut.ParentElement.innerHTML = preProcessOut.OriginalText;
}
} else if (inputType == "SUBMIT" || inputType == "BUTTON") {
control.value = preProcessOut.OriginalText;
}
} else if (nodeName == "SELECT" || nodeName == "SPAN") {
SetLabelText(control.id, preProcessOut.OriginalText);
} else {
control.innerHTML = preProcessOut.OriginalText;
}
}
if (typeof(clientCallBack) == "function") {
clientCallBack(result, clientCallBackArg);
}
}
function Anthem_FireCallBackEvent(
control,
e,
eventTarget,
eventArgument,
causesValidation,
validationGroup,
imageUrlDuringCallBack,
textDuringCallBack,
enabledDuringCallBack,
preCallBackFunction,
postCallBackFunction,
callBackCancelledFunction,
includeControlValuesWithCallBack,
updatePageAfterCallBack
) {
// Cancel the callback if the control is disabled. Although most controls will
// not raise their callback event if they are disabled, the LinkButton will.
// This check is for the LinkButton. See SourceForge Patch 1639700.
if (control.disabled) return;
var preProcessOut = new Anthem_PreProcessCallBackOut();
var preProcessResult = Anthem_PreProcessCallBack(
control,
e,
eventTarget,
causesValidation,
validationGroup,
imageUrlDuringCallBack,
textDuringCallBack,
enabledDuringCallBack,
preCallBackFunction,
callBackCancelledFunction,
preProcessOut
);
if (preProcessResult) {
var eventType = e.type;
Anthem_FireEvent(
eventTarget,
eventArgument,
function(result) {
Anthem_PostProcessCallBack(
result,
control,
eventType,
eventTarget,
null,
null,
imageUrlDuringCallBack,
textDuringCallBack,
postCallBackFunction,
preProcessOut
);
},
null,
includeControlValuesWithCallBack,
updatePageAfterCallBack
);
}
}
function AnthemListControl_OnClick(
e,
causesValidation,
validationGroup,
textDuringCallBack,
enabledDuringCallBack,
preCallBackFunction,
postCallBackFunction,
callBackCancelledFunction,
includeControlValuesWithCallBack,
updatePageAfterCallBack
) {
var target = e.target || e.srcElement;
if (target.nodeName.toUpperCase() == "LABEL" && target.htmlFor != '')
return;
var eventTarget = target.id.split("_").join("$");
Anthem_FireCallBackEvent(
target,
e,
eventTarget,
'',
causesValidation,
validationGroup,
'',
textDuringCallBack,
enabledDuringCallBack,
preCallBackFunction,
postCallBackFunction,
callBackCancelledFunction,
true,
true
);
}
// Returns the top, left control location in FireFox
function GetControlLocation(control) {
var offsetX = 0;
var offsetY = 0;
var parent;
for (parent = control; parent; parent = parent.offsetParent) {
if (parent.offsetLeft) {
offsetX += parent.offsetLeft;
}
if (parent.offsetTop) {
offsetY += parent.offsetTop;
}
}
return { x: offsetX, y: offsetY };
}
function GetLabelText(id) {
var labels = document.getElementsByTagName('label');
for (var i = 0; i < labels.length; i++) {
if (labels[i].htmlFor == id) {
return labels[i].innerHTML;
}
}
return null;
}
function SetLabelText(id, text) {
var labels = document.getElementsByTagName('label');
for